WO2004079750A1 - Cask, composition for neutron shielding body, and method of manufacturing the neutron shielding body - Google Patents

Cask, composition for neutron shielding body, and method of manufacturing the neutron shielding body Download PDF

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Publication number
WO2004079750A1
WO2004079750A1 PCT/JP2003/013944 JP0313944W WO2004079750A1 WO 2004079750 A1 WO2004079750 A1 WO 2004079750A1 JP 0313944 W JP0313944 W JP 0313944W WO 2004079750 A1 WO2004079750 A1 WO 2004079750A1
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WO
WIPO (PCT)
Prior art keywords
neutron
composition
neutron shielding
powder
increasing agent
Prior art date
Application number
PCT/JP2003/013944
Other languages
French (fr)
Japanese (ja)
Inventor
Nobuo Ishihara
Katsunari Ohsono
Kiichiro Sakashita
Kiyoshi Ono
Makio Atsumi
Original Assignee
Mitsubishi Heavy Industries, Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2003055828A external-priority patent/JP4115299B2/en
Application filed by Mitsubishi Heavy Industries, Ltd. filed Critical Mitsubishi Heavy Industries, Ltd.
Priority to KR1020047019785A priority Critical patent/KR100706012B1/en
Priority to US10/513,333 priority patent/US7327821B2/en
Priority to EP03770037A priority patent/EP1600984B1/en
Publication of WO2004079750A1 publication Critical patent/WO2004079750A1/en

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Classifications

    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
    • G21F1/00—Shielding characterised by the composition of the materials
    • G21F1/02—Selection of uniform shielding materials
    • G21F1/10—Organic substances; Dispersions in organic carriers
    • G21F1/103—Dispersions in organic carriers
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
    • G21F9/00—Treating radioactively contaminated material; Decontamination arrangements therefor
    • G21F9/28—Treating solids
    • G21F9/34—Disposal of solid waste
    • G21F9/36—Disposal of solid waste by packaging; by baling
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21C—NUCLEAR REACTORS
    • G21C19/00—Arrangements for treating, for handling, or for facilitating the handling of, fuel or other materials which are used within the reactor, e.g. within its pressure vessel
    • G21C19/32—Apparatus for removing radioactive objects or materials from the reactor discharge area, e.g. to a storage place; Apparatus for handling radioactive objects or materials within a storage place or removing them therefrom
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
    • G21F1/00—Shielding characterised by the composition of the materials
    • G21F1/02—Selection of uniform shielding materials
    • G21F1/10—Organic substances; Dispersions in organic carriers
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
    • G21F5/00—Transportable or portable shielded containers
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21F—PROTECTION AGAINST X-RADIATION, GAMMA RADIATION, CORPUSCULAR RADIATION OR PARTICLE BOMBARDMENT; TREATING RADIOACTIVELY CONTAMINATED MATERIAL; DECONTAMINATION ARRANGEMENTS THEREFOR
    • G21F5/00—Transportable or portable shielded containers
    • G21F5/005—Containers for solid radioactive wastes, e.g. for ultimate disposal
    • G21F5/008—Containers for fuel elements
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00—Energy generation of nuclear origin
    • Y02E30/30—Nuclear fission reactors

Definitions

  • the present invention relates to a composition for a neutron shield, and more particularly to a composition for manufacturing a neutron shield suitable for a cask for storing and transporting spent fuel. Also, this neutron
  • the present invention relates to a cask using a composition for a shield. book
  • a substance having a high hydrogen density that is, a substance having a high hydrogen content is effective for shielding fast neutrons.
  • a substance having a high hydrogen density that is, a substance having a high hydrogen content is effective for shielding fast neutrons.
  • water, paraffin, polyethylene, or the like can be used as the neutron shield.
  • This liquid, such as water, is lighter than concrete, but it is
  • the neutron shielding ability of the material of the container itself that stores the night body such as water is a problem.
  • Thermosetting resins such as polyolefin-based thermoplastic resins such as paraffin and polyethylene, unsaturated polyester resins, and epoxy resins A mixture of such a resin and a small amount of a boron compound as a neutron shielding material is used.
  • gamma rays are shielded by arranging a ray shielding structure that covers the outside of the neutron shield body.
  • neutron shields have been developed that can maintain a certain level of neutron shielding ability even in the event of a fire.
  • a neutron shielding body in which a large amount of aluminum hydroxide powder, magnesium hydroxide powder, or the like is blended as a refractory material has been proposed (Japanese Patent Application Laid-Open No. 2001-1088787, Patent No. 3 15 0 6 7 2) ⁇
  • the neutron shields made of resin, etc., which are currently mainly used, have a small specific gravity of 0.9 to 1.2, and are generated when high-speed neutrons are shielded. It is not suitable for shielding gamma rays. Therefore, it was necessary to arrange a gamma-ray shielding structure using a material with a large specific gravity outside the neutron shield body. In other words, the neutron shield itself could not satisfy the neutron shielding ability and the gamma ray shielding.
  • the dehydration and thermal decomposition temperature of aluminum hydroxide is 245 ° C to 320 ° C
  • the dehydration and thermal decomposition temperature of magnesium hydroxide is 340 ° C. Since the temperature is 390 ° C, it is considered that hydroxy-magnesium powder is more suitable as a refractory material. It is.
  • magnesium hydroxide powder is used, the viscosity of the composition increases, and it takes a lot of time and effort for kneading and filling.Voids trapped inside the resin remain, and neutron shielding occurs. There is a problem that performance may be reduced.
  • the present invention has been made in view of the above, and has as its object to provide a neutron shielding composition excellent in fire resistance, which effectively shields neutrons and wires, and a cask using the same. . Another object is to provide a neutron shielding composition having good workability. Disclosure of the invention
  • An object of the present invention is to solve at least the above-mentioned problems.
  • a cask of the present invention comprises: a trunk body having a basket formed of a square pipe or a plate-like member constituting a cell for storing a spent fuel assembly; and a trunk body and an outer cylinder provided on an outer periphery thereof. It is characterized by having a neutron shield filled with a neutron shield composition containing a neutron shielding material mainly composed of a polymer, a refractory material and a density increasing agent.
  • a cask of the present invention comprises: a trunk body having a basket formed of a square pipe or a plate-like member constituting a cell for storing a spent fuel assembly; and a trunk body and an outer cylinder provided on an outer periphery thereof.
  • the composition for a neutron shield of the present invention is a composition for producing a neutron shield suitable for a cask, and a neutron shielding material mainly composed of a polymer and a particle size of 1.5 to 15 ⁇ m. And magnesium hydroxide powder.
  • the composition for a neutron shield of the present invention is a composition for producing a neutron shield suitable for a cask, and includes a neutron shielding material mainly composed of a polymer, a refractory material, and a density increasing agent. It is characterized by containing.
  • the neutron shielding composition of the present invention is a composition for producing a neutron shielding suitable for a cask, and contains 20 to 55 mass of a neutron shielding material mainly composed of a polymer. / 0 , 4 to 55% by mass of the curing agent, 5 to 60% by mass of the refractory material, 5 to 40% by mass of the density increasing agent, and 0.5 to 10% of the boron compound. % By mass.
  • the method for producing a neutron shield of the present invention comprises producing a neutron shield which contains a neutron shielding material mainly composed of a polymer as a constituent component and can enhance the neutron shielding effect while maintaining the ⁇ -ray shielding performance.
  • a neutron shielding composition by replacing a component other than the polymer-based neutron shielding material with a density-increasing agent, thereby increasing the specific gravity of the neutron shielding composition to 1.62 to 1.72 g. and maintains the / cm 3.
  • FIG. 1 is a conceptual diagram showing one embodiment of the neutron shielding composition according to the present invention
  • FIG. 2 is a graph showing the relationship between the density increasing agent and the hydrogen content in the neutron shielding composition according to the present invention
  • FIG. 3 is a characteristic diagram showing the relationship between the density of the density-increasing agent according to the present invention and the relative ratio of neutron beam + secondary ⁇ dose outside the neutron shield.
  • FIG. 5 is a perspective view showing a configuration of a cask applied to the present invention.
  • FIG. 5 is an axial cross-sectional view showing a configuration of the cask shown in FIG. 4
  • FIG. 6 is a diagram shown in FIG. FIG.
  • FIG. 7 is an explanatory view showing an outline of a cask having a trunk body having a basket formed of a plate-like member inside
  • FIG. 8 is a fireproof
  • FIG. 3 is a view showing a test container.
  • the composition for a neutron shielding body is a mixture of a neutron shielding material mainly composed of a polymer as a main component, a curing agent, and a boron compound as basic components. Flame retardancy can be imparted by mixing a refractory material with this basic component. Further, by mixing carbon powder and z or a density increasing agent, the Y-ray shielding ability, neutron shielding ability, workability, and the like can be further improved.
  • each component will be described in detail, but a commercially available component can be used unless otherwise specified.
  • Typical examples of the neutron shielding material mainly composed of a polymer include a polyolefin resin such as polyethylene, polypropylene, and polyethylene, and an epoxy resin.
  • Epoxy resin means a resin containing a crosslinkable epoxy group.
  • Epoxy resins include, for example, glycidyl ether type / bifunctional phenol type epoxy resin, glycidyl ether type / polyfunctional phenol type epoxy resin, glycidyl ether type / alcohol type epoxy resin, glycidyl ester type epoxy resin, fat Group epoxy resins, alicyclic epoxy resins, modified epoxy resins, and the like. Further, hydrogenated epoxy resins obtained by adding hydrogen to the ring structure of these epoxy resins, and the like are also included. Among them, a hydrogenated epoxy resin is preferable.
  • the epoxy resin may be a single type of epoxy resin or a mixture of two or more types of epoxy resins.
  • epoxy resins include, as dalicidyl ether type / bifunctional phenol type epoxy resins, bisphenol mono type epoxy resins, stilbene type epoxy resins, biphenyl type epoxy resins, and monocyclic epoxy resins.
  • Glycidyl ether / polyfunctional phenolic epoxy resins such as polyaromatic epoxy resins and condensed polycyclic aromatic epoxy resins, include polyphenol epoxy resins and phenol novolak resins.
  • Aliphatic epoxy resins such as epoxy resins, methylene group-substituted phenol novolak epoxy resins, alkylene-modified phenol novolak epoxy resins, aralkyl-modified phenol novolak epoxy resins, etc.
  • Modified epoxy resins such as formula epoxy resins, alicyclic epoxy resins by glycidyl etherification of functional groups, cyclopentagon-type epoxy resins, and chain-chain aliphatic epoxy resins include silicone-modified epoxy resins, urethane-modified epoxy resins, and polyimidines. And a polyamide-modified epoxy resin, a photocurable epoxy resin, and the like, and other examples include a phosphorus-containing epoxy resin, a sulfur-containing epoxy resin, and a nitrogen-containing epoxy resin.
  • the hydrogenated epoxy resin include a hydrogenated bisphenol A-type epoxy resin, a hydrogenated potassium bisphenol F-type epoxy resin, and a resin obtained by hydrogenating a novolak-type glycidyl ether resin.
  • non-hydrogenated epoxy resins bisphenol-type epoxy resins and aliphatic epoxy resins are preferred.
  • a hydrogenated epoxy resin and a hydrogenated bisphenol A type epoxy resin obtained by adding hydrogen to the ring structure of a bisphenol type epoxy resin.
  • the content of the neutron shielding material mainly composed of polymer fluctuates depending on the material used, the type and content of other components, etc., so it is difficult to specify the force. In the whole, it is 20 to 55 mass%, preferably 24 to 47 mass%, and particularly preferably 35 to 42 mass%. 2 0 is less than mass% be prone neutron shielding ability is weakened, because when it exceeds 5 5 mass 0/0 poor Palance with other components.
  • a suitable curing agent is selected depending on the type of neutron shielding material mainly composed of a polymer.
  • the curing agent that reacts with the epoxy resin to form a crosslinked structure include amine-based curing agents, acids and acid anhydride-based curing agents, phenol-based curing agents, and the like.
  • a system curing agent is used.
  • amine-based curing agents sclerosing agents having a ring structure such as alicyclic amine-based curing agents and aromatic amine-based curing agents are preferably used in the composition of the present invention because of their high heat resistance.
  • the curing agent may be a single curing agent or a mixture of two or more curing agents.
  • the preferred amount of the curing agent it varies depending on the type of the curing agent used, the type and content of other components, and the like. It is 4 to 55% by mass, preferably 4.5 to 30% by mass, particularly preferably 6 to 15% by mass in the whole product. When the amount is less than 4% by mass / 0 , the effect as a curing agent is weak, and when the amount exceeds 55% by mass, hardening becomes too fast, and the working time required for filling or the like cannot be secured.
  • Fireproofing is added to keep the neutron shield so that it can maintain a certain level of neutron shielding capacity when the neutron shield is exposed to high temperatures, for example, when a fire occurs.
  • compounds such as aluminum hydroxide and magnesium hydroxide.
  • Magnesium hydroxide has a dehydration decomposition temperature of 340 ° C. to 390 ° C., which is higher than the dehydration decomposition temperature of hydroxide aluminum, so that it is particularly suitable as a refractory material.
  • magnesium hydroxide is in powder form.
  • the particle size of the magnesium hydroxide powder is not usually adjusted. By adjusting the particle size, the composition becomes more suitable as a composition for a neutron shield.
  • the preferred particle size of the magnesium hydroxide powder is 1.5 to 15 m, and particularly preferably 1.5 to 5 ⁇ m.
  • Commercially available magnesium hydroxide powder having these particle sizes can be used.
  • the particle size of the magnesium hydroxide powder is desirably such that the particle size of all the powders is in the range of 1.5 to 15 ⁇ m, but in reality, 80% or more of the magnesium hydroxide powder is 1%.
  • magnesium hydroxide powder having a particle size of less than 1.5 ⁇ is used and the mixing ratio of magnesium hydroxide powder is increased, the viscosity increases and a great deal of time and effort is required for kneading and filling. Therefore, the mixing ratio of magnesium hydroxide powder is kept low, and the fire resistance deteriorates.
  • magnesium hydroxide powder having a particle size of more than 15 im is used, the total surface area of the magnesium hydroxide powder becomes small, so that fire resistance may be reduced. In other words, by using 1.5-15 ⁇ m magnesium hydroxide powder, neutron shielding with good workability that does not require much time and labor for kneading and filling while maintaining fire resistance A body composition can be obtained.
  • the viscosity of the resin before curing be 10 OPa • s or less in order to eliminate voids when pouring the epoxy resin before curing into a container.
  • the amount of magnesium hydroxide powder should be less than 30% by mass to maintain proper viscosity. At the temperature (800 ° C for 30 minutes), voids may be generated inside the resin and the neutron shielding ability may be reduced.
  • the mixing amount of magnesium hydroxide powder can be 50% by mass or more, but since the surface area of magnesium hydroxide powder decreases, At the refractory temperature (outside 800 ° C, 30 minutes), voids may be generated inside the resin and the neutron shielding ability may be reduced.
  • aluminum hydroxide is superior to hydroxymagnesium in terms of hydrogen content
  • aluminum hydroxide powder and magnesium hydroxide powder may be appropriately mixed to form a refractory material.
  • the soda content (Na 2 ⁇ ) By setting the soda content (Na 2 ⁇ ) to 0.07 mass% or less, the hydrogen content can be maintained up to 150 ° C or more.
  • a refractory material other than aluminum hydroxide powder and magnesium hydroxide powder may be further added.
  • the amount of the refractory material to be added because it varies depending on the type of refractory material used, the type and content of other components, etc., but it is preferably 5 to 60% by mass, particularly Preferably it is 33 to 41% by mass. If it is less than 5% by mass, the effect as a fire material is weak, and if it exceeds 60% by mass, the proportion of neutron shielding materials, etc. mainly composed of polymers becomes small, and the neutron absorption capacity is reduced.
  • the density enhancer is a high-density material, and any material can be used as long as the specific gravity of the neutron shield can be increased, as long as it does not adversely affect other components.
  • the density of the density-increasing agent itself that effectively blocks y-rays is 5.0 g / cm 3 or more, preferably 5.0 to 22.5. More preferably 6.0 ⁇ 1 5 g / cm 3. If it is less than 5.0 g / cm 3 , it is difficult to effectively shield ⁇ -rays without impairing the neutron shielding ability, and if it exceeds 22.5 g / cm 3 , the effect according to the amount of added syrup is recognized. I can't.
  • a metal powder or a metal sardine powder may be used.
  • a metal having a melting point of 350 ° C or more such as Cr, Mn, Fe, Ni, Cu, Sb, Bi, U, W, and / or a melting point of 1000 ° N i O a Sani ⁇ of C or more metals, Cu_ ⁇ , ZnO, Z r 0 2, SnO, Sn_ ⁇ 2, W_ ⁇ 2, U_ ⁇ 2, P b 0, W0 3, lanthanoid oxides 6.
  • Cu, W0 2, W_ ⁇ 3, Z R_ ⁇ 2, Ce_ ⁇ 2 is particularly preferred. This is because it has an advantage in cost.
  • the density increasing agent may be used singly or as a mixture of two or more.
  • the particle size is not particularly limited, but if the particle size is large, the density increasing agent may settle during production. The particle size that does not settle cannot be simply specified by a numerical value because it is largely affected by other conditions (eg, the temperature, viscosity, curing rate, etc. of the composition).
  • the specific gravity of the middle-I viable shield can be increased, and the line can be more effectively shielded.
  • the use of the above metal powder or metal oxide powder can improve the fire resistance.
  • the hydrogen content can be increased by replacing some of the additives other than the neutron shielding material mainly composed of polymers, mainly some of the refractory materials, with a density increasing agent.
  • a neutron shield having a high hydrogen content can be manufactured, and neutrons can be effectively shielded. In other words, it is possible to achieve both neutron shielding ability and ⁇ / ray shielding.
  • the amount of the density increasing agent to be mixed can be appropriately adjusted and added so as to maintain the specific gravity (1.62 to 1.72 g / cm 3 ) of the neutron shielding composition. Specifically, it is difficult to specify because it varies depending on the type of density increasing agent used, the type and content of other components, etc., for example, 5 to 40 mass% in the whole composition %, Preferably 9 to 35 mass. / 0 . When using the C e 0 2, 1 5 ⁇ 2 0 % by mass, especially. 5 mass. /. When the amount is less than 40% by mass, it is difficult to maintain the specific gravity of the composition in the range of 1.62 to 1.72 g / cm 3 .
  • a specific example of an embodiment using a density increasing agent will be described in detail with reference to the drawings.
  • FIG. 1 is a conceptual diagram showing a configuration example of a neutron shield according to the present embodiment.
  • the hatched portion in the figure schematically shows the amount of hydrogen.
  • the neutron shield according to the present embodiment is a polymer
  • This is a mixture of a neutron shielding material 1 mainly composed of a refractory material 2 and a density increasing agent 3 having a higher density than the refractory material 2.
  • the density increasing agent 3 by mixing metal powder or metal oxide powder, the density of hydrogen is maintained while maintaining the density of the material (from 1.62 to 1.72 gZmL). Neutron shield.
  • the density of the density increasing agent 3 to be mixed is at least 5. Og / mL, preferably 5.0 to 22.5 g / mL, and more preferably 6.0 to 15 gZmL.
  • the density increasing agent 3 it is preferable to mix a metal powder having a melting point of 350 ° C or more or an oxide powder of a metal having a melting point of 1000 ° C or more.
  • powder materials corresponding to these include metals such as Cr, Mn, Fe, Ni, Cu, Sb, Bi, U, and W.
  • an oxide of a metal like for example NiO, CuO, Z nO, Zr_ ⁇ 2, SnO, S N_ ⁇ 2, W0 2, Ce_ ⁇ 2, U0 2, P b 0 , P b 0, W0 3 and the like
  • NiO, CuO, Z nO, Zr_ ⁇ 2, SnO, S N_ ⁇ 2, W0 2, Ce_ ⁇ 2, U0 2, P b 0 , P b 0, W0 3 and the like can be
  • the neutron shielding material 1 mainly composed of a polymer includes, for example, polyolefin-based resins such as polyethylene, polypropylene, and polybutylene, and epoxy resins.
  • the neutron shielding material (resin) 1 mainly composed of a high molecule is provided with a refractory material 2 and a density higher than the refractory material 2.
  • the hydrogen content can be increased while maintaining the density at a constant value (in the range of 1.62 to 1.72 g / mL).
  • the refractory material 2 has a slightly higher density than the neutron shielding material 1 and contains slightly less hydrogen.
  • a part of the refractory material 2 is replaced with a density increasing agent 3 containing no hydrogen so that the densities are equal.
  • the hydrogen content is slightly smaller, and 2 parts of the refractory material are replaced with high hydrogen neutron shielding material 1.
  • the hydrogen content can be increased.
  • the density of the density increasing agent 3 to be mixed is set to 5.OgZmL or more, preferably 5.0 to 22.5 g / mL, more preferably 6.0 to 15 gZmL.
  • FIG. 2 is a characteristic diagram showing the relationship between the density of the density increasing agent 3 and the hydrogen content.
  • the hydrogen content is 0.0969 g / mL and the refractory material 2 (magnesium hydroxide) is included in the base resin 1 with a density of 1.64 g / mL. It shows the hydrogen content when refractory material 2 was replaced with density increasing agent 3.
  • the density of magnesium hydroxide, which is the refractory material 2 is 2.36 g / mL. As can be seen from Fig. 2, in order for the effect to be recognized, it is not necessary to set the density of the density increasing agent to be higher than that of refractory material 2 (2.36 g / mL).
  • the density differs depending on the combination of the base resin 1 and the refractory material 2, but the boundary is a density slightly higher than the density of the refractory material 2 (2.36 g / mL).
  • the effect is observed when the density of the density increasing agent 3 is 5.0 g / mL or more, preferably 6.0 g / mL or more. If the density of Density Increasing Agent 3 exceeds 22.5 g / mL, the effect according to the amount added is not observed.
  • FIG. 3 is a characteristic diagram showing the relationship between the density of the density increasing agent 3 and the relative neutron beam + secondary ⁇ dose outside the neutron shield.
  • the hydrogen content is 0.0969 g / mL
  • the refractory material 2 (magnesium hydroxide) is contained in the base resin 1 with a density of 1.64 gZmL.
  • Fig. 3 shows the shielding effect when the refractory material 2 was replaced with the density increasing agent 3. Note that the shielding outside dose of base resin 1 is 1. From FIG. 3, it can be seen that the effect is recognized because the density of the density increasing agent 3 is at least 5. Og / m, more preferably at least 6. OgZmL. If the density of the density increasing agent 3. exceeds 22.5 gZmL, the effect according to the added amount is not recognized.
  • metal powder (Cr, Mn, Fe, Ni, Cu, Sb, Bi, U, W, etc.) having a melting point of 350 ° C or more is mixed as the density increasing agent 3.
  • metals NiO, C uO,, ZnO, Zr_ ⁇ 2, SnO, S n 0 2, W0 2, Ce_ ⁇ 2, U_ ⁇ 2, P b 0, P b O, by which a mixture of wo 3), it is possible to improve the fire resistance.
  • the neutron shield according to the present embodiment it is possible to increase the hydrogen content while maintaining a constant value without reducing the material density. It is possible to improve neutron shielding performance without arranging gamma-ray shielding structures on the outside.
  • the neutron shield according to the present embodiment also includes, as shown in FIG. 1, an epoxy resin having a low hydrogen content, which is a neutron shielding material 1 mainly composed of a polymer, a refractory material 2, and a refractory material 2. Also, the mixture is mixed with a density increasing agent 3 having a high density and subjected to a shaping process.
  • an epoxy resin having a low hydrogen content which is a neutron shielding material 1 mainly composed of a polymer, a refractory material 2, and a refractory material 2.
  • the mixture is mixed with a density increasing agent 3 having a high density and subjected to a shaping process.
  • a neutron shield obtained by curing an epoxy resin having a low hydrogen content by mixing a metal powder or a metal oxide powder.
  • the density of the density increasing agent 3 to be mixed is 5. OgZmL or more, preferably 5.0 to 22.5 g / mL, more preferably 6.0 to 15 g / mL.
  • the density increasing agent 3 it is preferable to mix metal powder having a melting point of 350 ° C. or more, or to mix metal oxide powder having a melting point of 1000 ° C. or more.
  • powder materials corresponding to these include metals such as Cr, Mn, Fe, Ni, Cu, Sb, Bi, U, and W.
  • NiO NiO, CuO, Zn_ ⁇ , Zr_ ⁇ 2, SnO, S N_ ⁇ 2, W0 2, Ce_ ⁇ 2, U_ ⁇ 2, P b 0, P B_ ⁇ , W_ ⁇ 3, and the like.
  • the neutron shielding material 1 mainly composed of a polymer
  • a polyolefin resin such as polyethylene, polypropylene, polybutylene, or the like can be cited as a typical example.
  • a neutron shielding material 1 mainly composed of a high molecule is added to a refractory material 2 and a density increasing agent 3 having a higher density than the refractory material 2.
  • a density increasing agent 3 having a higher density than the refractory material 2.
  • the refractory material 2 has a slightly higher density than the neutron shielding material 1 and contains slightly less hydrogen.
  • a part of the refractory material 2 is replaced with a density increasing agent 3 containing no hydrogen so that the densities are equal.
  • the hydrogen content is slightly smaller, and 2 parts of the refractory material is replaced with high-hydrogen neutron shielding material 1 and the hydrogen content is reduced. Can be increased.
  • the density of the density increasing agent 3 to be mixed is set to 5.0 gZmL or more, preferably 5.0 to 22.5 gZmL, more preferably 6.0 to 5.0 gZmL.
  • the amount is set to 15 g / mL, the above-mentioned effects can be more remarkably exhibited.
  • FIG. 2 is a characteristic diagram showing the relationship between the density of the density increasing agent 3 and the hydrogen content.
  • the base resin 1 with a nitrogen content of 0.0969 g / mL and a refractory material 2 (magnesium hydroxide) with a density of 1.64 g / mL was added to the base resin 1.
  • a refractory material 2 magnesium hydroxide
  • the density of magnesium hydroxide, which is refractory material 2 is 2.36 g / mL.
  • the boundary is a density slightly higher than the density of the refractory material 2 (2.36 g / mL), although it depends on the combination of the base resin 1 and the refractory material 2.
  • the effect is observed when the density of the density increasing agent 3 is 5.0 g / mL or more, more preferably 6.0 g / mL or more.
  • the density of the density increasing agent 3 exceeds 22.5 gZmL, the effect according to the added amount is not recognized.
  • FIG. 3 is a characteristic diagram showing the relationship between the density of the density increasing agent 3 and the relative neutron beam + secondary ⁇ dose outside the neutron shield.
  • the hydrogen content is 0.0969 gm L and the refractory material 2 (magnesium hydroxide) contains 1.64 g / mL base resin 1 so that the density is constant. This shows the shielding effect when 2 is replaced with the density increasing agent 3.
  • the shielding outside dose of the base resin 1 is set to 1.
  • the effect is recognized when the density of the density-enhancing agent 3 is 5.0 g / mL or more, preferably 6. Og / mL or more. Note that if the density of the density increasing agent 3 exceeds 22.5 g / mL, no effect according to the amount of the added kashi can be observed.
  • metal powder having a melting point of 350 ° C. or more (Cr, Mn, Fe, Ni, Cu, Sb, Bi, U, W, etc.) is used as the density increasing agent 3.
  • mixing force or melting point 1000 ° C or more metal oxides powder (NiO, C uO,, ZnO, Zr_ ⁇ 2, SnO, Sn_ ⁇ 2, W_ ⁇ 2, Ce_ ⁇ 2, U_ ⁇ 2, P b 0 , PbO and wo 3 ) can improve the fire resistance.
  • the boron compound is blended in a small amount and has a function as a neutron moderator and absorber.
  • the boron compound to be incorporated in the neutron shield in a trace amount may be any compound having a neutron absorption capability, such as boron nitride, boric anhydride, and boron iron having a large absorption cross section for slow and thermal neutrons.
  • boron compounds such as orthoboric acid, boron carbide, and metaboric acid. Boron carbide is particularly preferred. This is because it has high chemical stability (does not change with temperature, does not absorb moisture, etc.) and does not affect neutron shielding materials mainly composed of polymers.
  • the boron compound one kind of boron compound may be used, or two or more kinds of boron compounds may be mixed and used.
  • the boron compound is used in the form of a powder, and the particle size and the amount added can be adjusted appropriately and added.
  • the average particle size is preferably about 1 to 200 ⁇ m, more preferably about 100 to 100 m, and more preferably about 20 to 100 ⁇ m. About 50 ⁇ is particularly preferred. Since the amount of addition varies depending on the type of the boron compound used, the type and content of other components, etc., it is difficult to specify the amount.
  • the amount is 0.5 to 10% by mass in the whole composition. And particularly preferably 0.5 to 3% by mass. When the amount is less than 0.5% by mass, the effect of the added boron compound as a neutron shielding material is low. When the amount exceeds 10% by mass, it becomes difficult to uniformly disperse the boron compound.
  • a preferable composition for a neutron shielding body from the viewpoint of neutron shielding ability, ⁇ -ray shielding ability, and fire resistance is hydrogenated epoxy resin: 38 wt. /. , Amine-based curing agent: 8 wt%, the refractory material (M g OH 2): 3 5 wt%, the density increasing agent (C e 0 2): 1 8 wt%, B 4 C: consisting of 1 wt% of the composition It is a composition for a neutron shield.
  • Carbon powder is added to further improve the neutron shielding ability.
  • the temperature of the refractory condition (external temperature: 800 ° C, 30 minutes) in a sealed vessel with a melting stopper, the voids are generated inside the resin and the neutron shielding ability is reduced. There is a risk.
  • carbon powder is added, the generation of voids is suppressed, and the neutron shielding ability is further improved.
  • the carbon powder to be added is, for example, carbon black, graphite, activated carbon and the like, and carbon black is particularly preferred. This is because it has advantages in ease of purchase and cost.
  • the carbon powder one type of carbon powder may be used, or two or more types of carbon powder may be mixed and used.
  • the amount of addition can be adjusted appropriately according to the type of carbon powder, and in the case of carbon black, it is preferably from 0.02 to 4% by mass, and from 0.05 to 0.3% by mass. Les, especially preferred.
  • the effect is recognized at 0.02% by mass or more, and the effect is particularly remarkable at 0.05% by mass or more. At less than 0.3% by mass, no remarkable increase in viscosity is observed.
  • the content exceeds 4% by mass, the viscosity sharply increases with the addition of the carbon powder, and the hydrogen content decreases by the amount added, so that no effect commensurate with the added amount is observed.
  • the particle size is not particularly limited, it is preferable that the particle size is small enough to prevent sedimentation since the particle size is large and the carbon powder may settle during the production.
  • the particle size that does not settle cannot be simply specified by a numerical value because it is largely affected by other conditions (eg, the temperature, viscosity, curing rate, etc. of the composition).
  • the neutron shielding composition of the present invention contains, as fillers, powders such as silica, anoremina, calcium carbonate, trimonium antimony, titanium oxide, asbestos, clay, and my powder, as well as glass fibers. And carbon fiber or the like may be added as needed. If necessary, natural waxes as release agents, metal salts of fatty acids, acid amides, fatty acid esters, etc., paraffin chloride, bromotoluene, hexabromotoluene, antimony trioxide, etc. as flame retardants Carbo as colorant Silane coupling agents, titanium coupling agents, etc., in addition to black and red iron oxides.
  • powders such as silica, anoremina, calcium carbonate, trimonium antimony, titanium oxide, asbestos, clay, and my powder, as well as glass fibers. And carbon fiber or the like may be added as needed.
  • natural waxes as release agents, metal salts of fatty acids, acid amides, fatty acid esters, etc
  • the composition of the present invention is prepared by mixing an epoxy resin with other components.
  • the neutron shield is obtained by molding a composition for a neutron shield.
  • Crosslinking of the epoxy resin during molding of the neutron shield can be performed at room temperature, but is preferably performed by heating. Specific conditions vary depending on the type, composition, and the like of the epoxy resin, but it is preferable to perform heating for 1 hour to 3 hours under a temperature condition of 50 to 200 ° C. Further, such a heat treatment is preferably performed in two stages.After heating at 60 to 90 for 1 to 2 hours, heat treatment at 120 to 150 for 2 to 3 hours is preferable. preferable.
  • Neutron shields are used to shield neutrons, for example, in casks for storing and transporting spent fuel.
  • a cask for transportation can be manufactured using a known technique.
  • the cask is a container that stores and stores the spent fuel assemblies that have been burned.
  • nuclear fuel assemblies that have been burned and have become unusable are called spent fuel (recycled fuel).
  • Spent fuel contains high radioactive materials such as fission products (FP) and needs to be thermally cooled. Therefore, it is cooled in a cooling pit of a nuclear power plant for a predetermined period (3 to 6 months). After that, they are stored in a cask, which is a shielding container, and transported and stored in a reprocessing facility by truck or ship.
  • FP fission products
  • FIG. 4 is a perspective view showing a cask.
  • FIG. 5 is an axial sectional view of the cask shown in FIG.
  • FIG. 6 is a radial sectional view of the cask shown in FIG.
  • the cask 100 is obtained by machining the inner surface of the cavity 102 of the body 101 so as to match the outer peripheral shape of the basket 130.
  • the inner surface of the cavity 102 is machined by milling or the like using a dedicated processing device.
  • the trunk body 101 and the bottom plate 104 are forged products made of carbon steel having a y-ray shielding function. In addition, carbon Stainless steel can be used instead of steel.
  • the trunk body 101 and the bottom plate 104 are joined by welding.
  • a metal gasket is provided between the primary lid 110 and the body 101 in order to ensure the sealing performance of the pressure vessel.
  • a resin 106 which is a polymer material containing a large amount of hydrogen and has a neutron shielding function, is filled with the neutron shielding composition described above.
  • a plurality of copper internal fins 107 for heat conduction are welded between the body 101 and the outer cylinder 105, and the resin 106 is connected to the internal fins 107. It is injected into a space formed by a pipe or the like (not shown) in a flowing state and cooled and solidified.
  • the internal fins 107 are preferably provided with a high density in a portion having a large amount of heat in order to uniformly radiate heat.
  • a thermal expansion margin 108 of several mm is provided between the resin 106 and the outer cylinder 105.
  • the thermal expansion margin 108 dispose the heat dissipation adhesive with a heater embedded in a hot-melt adhesive, etc. on the inner surface of the outer cylinder 105, inject and solidify the resin 106, and then heat and melt and discharge the heater. It is formed by
  • the shank 1 109 is composed of a primary lid 110 and a secondary lid 111.
  • the primary sandalwood 1 1 '0 is in the form of a disk made of stainless steel or carbon steel that blocks gamma rays.
  • the secondary lid 111 is also a disk made of stainless steel or carbon steel, and the upper surface thereof is filled with a resin 112 as a neutron shield, that is, the neutron shield described above.
  • the primary lid 110 and the secondary lid 111 are attached to the trunk body 101 by bolts 113 made of stainless steel or carbon steel. Further, metal gaskets are provided between the primary lid 110 and the secondary lid 111 and the trunk main body 101, respectively, to maintain the internal sealing performance. Further, an auxiliary shield 115 enclosing the resin 114 is provided around the lid 109.
  • FIG. 4 shows the case where the auxiliary shield 115 is provided, when the cask 100 is transported, the auxiliary shield 115 is removed and the buffer 118 is attached (FIG. 5). See).
  • the cushion 1 18 is made of stainless steel It has a structure in which a cushioning material 119 such as a reddish material is incorporated in an outer cylinder 120 created by the above method.
  • the basket 130 is composed of sixty-nine square pipes 13 2 constituting a cell 13 1 for storing a spent fuel assembly.
  • For the square pipe 132 use is made of an aluminum composite material or an aluminum alloy obtained by adding a powder of B or B compound having neutron absorption performance to aluminum or aluminum alloy powder.
  • a neutron absorber force domes can be used in addition to boron.
  • the above-described cask 100 is a large-scale device of a 100-ton class, and by using the neutron shielding composition of the present invention as the resin 106, 112, 114, a remarkably light weight is obtained. Neutron shielding capacity and heat resistance can be maintained, and at the same time, even in a complex structure having internal fins 107, the fluidity and pot life can increase. The time and labor required for loading the resin 106, 112, 114 can be reduced significantly.
  • composition of the present invention is suitably used for a cask having a trunk body having a basket formed of a plate-like member shown in FIG. 7 therein.
  • the space 209 surrounded by the trunk body 201, the outer cylinder 205, and the two heat transfer fins 207 contains a polymer containing a large amount of hydrogen, which has neutron shielding ability, in order to absorb neutrons
  • the resin, which is the material, that is, the neutron shielding composition described above is filled.
  • the neutron shield including the neutron shield composition shields neutrons emitted from the recycled fuel assembly, and suppresses neutrons leaking to the outside of the cask 200 to a regulated value or less.
  • composition of the present invention is not limited to such a shield in a cask.It can be used in various places in a device or facility for preventing neutron diffusion, and can effectively shield neutrons. Can be.
  • the neutron shielding ability was evaluated based on the heat resistance represented by the weight loss rate below.
  • Weight loss Most of the water is water, which contains a lot of hydrogen, which has the effect of slowing down neutrons.
  • the test result that the weight loss rate is large means that the water resistance is reduced due to the low heat resistance, and as a result, the neutron shielding ability is reduced.
  • the y-ray shielding ability is evaluated by the density (gZcm 3 ) of the neutron shielding composition. Density force S1.62 or later: L. About 72 gZc m 3 ⁇ -rays can be sufficiently shielded
  • the epoxy resin was stiffened with the composition shown in Table 1 and the heat resistance was compared.
  • the heat resistance was expressed as a weight loss rate when the container was kept at 200 ° C for 2,000 h in a closed container, opened at room temperature, and left overnight to remove volatile components.
  • the hydrogen content was generally measured with a CHN analyzer, and in this example, the hydrogen content was determined using a gas thermal conductivity detection type CHN analyzer. Magnesium hydroxide powder with a particle size of 3.3 ⁇ m was used.
  • Epoxy base agent EPICURE 801A (trade name) manufactured by Daito Sangyo
  • Fireproofing agent Comparative Example 1 Aluminum hydroxide powder CW-325LV manufactured by Sumitomo Chemical Examples 1, 2: Magnesium hydroxide powder Boron carbide manufactured by Ube Materials KS-44 manufactured by Kyoritsu Ceramics
  • Example 1 the heat resistance was greatly improved by changing the refractory agent from aluminum hydroxide powder to magnesium hydroxide powder.
  • magnesium hydroxide has a low hydrogen content, so if the hydrogen content is almost constant, the amount of refractory agent mixed must be reduced and the density will decrease.
  • gamma rays are generated when neutrons are absorbed, but the shielding ability of gamma rays is reduced because the shielding ability of gamma rays is almost proportional to the density.
  • copper powder was added together with magnesium hydroxide powder in order to prevent a decrease in density.
  • Epoxy base agent Comparative example 2 Epicure 801A (trade name) manufactured by Daito Sangyo
  • Comparative Example 3 A material obtained by adding hydrogenated bisphenol A of Epicure 801A manufactured by Daito Sangyo (hydrogenated bisphenol A type epoxy resin)
  • Refractory agent Comparative example 2 Aluminum hydroxide powder CW-325LV manufactured by Sumitomo Chemical Comparative example 3: Magnesium hydroxide powder Made by Sobeclay Boron carbide Made by Kyoritsu Ceramics
  • the epoxy resin was cured with the formulation in Table 3 and the heat resistance was compared.
  • the heat resistance was determined in the same manner as in Experimental Examples 1 and 2. Magnesium hydroxide powder having a particle size of 3.3 / 3 / im was used.
  • Epoxy base material Comparative Example 4 Epicure 801A (trade name) manufactured by Daito Sangyo
  • Example 3 A material obtained by adding hydrogen to bisphenol A of Epicure 801A manufactured by Daito Sangyo (hydrogenated bisphenol A type epoxy resin)
  • Refractory Comparative Example 4 Aluminum hydroxide powder Sumitomo Chemical CW-325LV 'Example 3: Magnesium hydroxide powder Ube Materials Boron carbide Kyoritsu Ceramics KS-44
  • Example 3 the density and hydrogen content were changed by changing the epoxy main agent to a hydrogenated product (hydrogenated bisphenol A type epoxy resin), the refractory agent to magnesium hydroxide powder, and further adding iron powder.
  • the quantity and heat resistance were improved. That is, the shielding property and heat resistance against neutron rays and ⁇ rays were improved.
  • Example 4 Use of magnesium hydroxide powder having a particle size of 1.5 to 15 m
  • the following commercially available epoxine material, magnesium hydroxide powder and boron carbide were mixed and degassed at room temperature under vacuum. It was poured into a mold of X50 ⁇ 10 Omm, cured at room temperature for 24 hours, and then completely cured at 130 ° C. for 24 hours to produce Sample 1 shown in FIG.
  • the viscosity after mixing the materials is generally set to 100 Pa's or less in consideration of workability in manufacturing the shield, but here, the test was performed using 30 Pa's as a guide. This was placed in a fireproof test container 5 shown in Fig.
  • the whole was sealed with a SUS steel plate, and a 5-mm diameter tin stopper was attached to the center of the upper surface test piece. Let stand for 30 minutes. In other words, it is not the fireproof condition of general materials, Fire resistance in a semi-closed state according to the use conditions of.
  • the fireproof test container 5 is taken out under the condition of room temperature and atmospheric atmosphere, a flame is observed for a while from the melting stopper, but the self-extinguishing will be performed soon.
  • the neutron shield was taken out, the internal state and the residual weight ratio were measured, and it was determined whether or not the neutron shield had a certain level of neutron shielding ability even after fire resistance.
  • the residual weight was determined by the same method as in the heat resistance of Experimental Examples 1 and 2, and the mixed viscosity was determined by using a B-type viscometer.
  • the arbitrary cross section of the neutron shield is divided into 1-Omm meshes, and it is determined whether there is at least one space penetrating therethrough. The formation of continuousiscus provides a path for neutrons to penetrate, greatly reducing neutron shielding capacity.
  • Epoxy main ingredient Daito Sangyo DT-448 (Bisphenol A derivative-containing mixed resin)
  • Epoxy curing agent Daito Sangyo 1-5731 (Amine curing agent)
  • Magnesium hydroxide powder particle size 50 m, 15 m, 5 im Sovreclay, particle size 3.3 ⁇ Ube Materials, * standing diameter 1.7 ⁇ , ⁇ . ⁇
  • Appearance probability of continuous void is 50% or more and less than 100%.
  • Appearance probability of continuous void is 0% or more and less than 50%.
  • magnesium hydroxide powder and carbon powder were added. The effect of was confirmed.
  • the carbon powder used was a carbon black (Model No. 05-1530-5) manufactured by Sigma / Redlitsch Japan.
  • the Ni powder used as the density increasing agent was made of Yamaishi Metal.
  • Table 6 there was a tendency for voids to be less likely to occur due to the synergistic effect of combining the two powders, magnesium hydroxide powder with a particle size of 1.5 to 15 ⁇ m and carbon powder. .
  • Example 7 An epoxy resin raw material obtained by adding 18.6 Wt% of a curing agent mainly containing alicyclic amine to 38.6 Wt% of a hydrogenated bisphenol A main agent was further added. 0 3 hydroxide Maguneshiumu powder (particle ⁇ adjustment) as a refractory material. 0 W t%, 1 to B 4 C as a neutron absorption adsorbents. 5 W was added t%, then further lead powder 1 7. 0 W Add t%, mix at room temperature under vacuum, pour this into a mold, and cure at room temperature for 1 day. The mixture was cured at 0 ° C. for 10 hours to obtain a neutron shield of Example 22.
  • composition of this material was analyzed to be 0.103 g / mL for hydrogen, 0.581 g / mL for carbon, 0.025 g / mL for nitrogen, 0.019 g / mL for boron, 0.187 g / mL for magnesium, and 0.279 / mL for lead. It was 1.64 Og / mL.
  • Example 25 As the density increasing agent other than lead in Example 22 (P b), Bi 2 0 3 ( Example 23), Zr0 2 (Example 24), Cu neutron shielding body (Example 25) was.
  • Table 7 is a table showing the results of comparing the neutron shielding performance of Examples 22, 23, and 24 with Comparative Example 8 (a neutron shield for a BWR metal cask) without the conventional metal powder addition.
  • the neutron shield for a BWR metal cask of Comparative Example 8 was manufactured and used as a conventional product.
  • Comparative Example 9 shows an example in which the hydrogen content and the density were adjusted using only aluminum hydroxide without adding metal powder or metal oxide powder.
  • Example 8 is 1)
  • Table 7 is a table showing the results of comparing the neutron shielding performance of Example 25 with Comparative Example 8 (a neutron shield for a BWR metal mask) without the addition of the conventional metal powder.
  • Example 25 in Table 7 by adding metal powder to a neutron shielding material mainly composed of a polymer, it is possible to use an epoxy that has no hydrogen content and has no increased hydrogen content. In addition, the same neutron shielding performance as the conventional product (neutron shield for BWR metal cask) can be secured. Thereby, the manufacturing process of the neutron shield can be simplified.
  • each of the above embodiments includes various stages of the invention.
  • various inventions can be extracted by an appropriate combination of a plurality of disclosed constituent features. For example, even if some components are deleted from all the components shown in the embodiments, at least one of the problems described in the section of the problem to be solved by the invention can be solved, and If at least one of the stated effects can be obtained, a configuration from which this component is deleted can be extracted as an invention.
  • the neutron shielding composition of the present invention contains a neutron shielding material mainly composed of a polymer and magnesium hydroxide powder having a particle size of 1.5 to 15 ⁇ m. Therefore, it is suitable for shielding neutrons and has excellent fire resistance. In addition, workability is improved because magnesium hydroxide powder with a controlled particle size is used. Further, by adding carbon powder, the neutron shielding ability can be further improved.
  • the composition for a neutron shielding body of the present invention contains a neutron shielding material mainly composed of a polymer, a refractory material and a density increasing agent, so that it is suitable for shielding neutrons and ⁇ -rays. Is excellent. Further, by selecting hydroxide magnesium powder as a refractory material and adjusting the particle size, workability can be improved. The neutron shielding ability can be further improved by adding carbon powder. In addition, it is possible to increase the hydrogen content while maintaining a constant value without lowering the density of the material, thereby enabling neutron radiation without disposing a gamma-ray shielding structure outside the neutron shield main body. Can improve the shielding performance.
  • composition for a neutron shielding body of the present invention comprises: 20 to 55% by mass of the neutron shielding material mainly composed of the polymer; 4 to 55% by mass of the curing agent; 660% by mass, and the density increasing agent is 5 ⁇ 40% by mass. /. And 0.5 to 10% by mass of a boron compound, so that it is suitable for shielding neutrons and ⁇ -rays and has excellent fire resistance.
  • the cask of the present invention has a neutron shield including the above-described composition for a neutron shield, it is possible to effectively shield neutrons and ⁇ -rays.
  • the hydrogen content can be increased by substituting a part of the additive other than the epoxy resin with a density increasing agent.
  • the specific gravity of the neutron shielding composition is maintained (1.6 2-1.72 g / cm 3 ) by partially substituting components other than the neutron shielding material mainly composed of polymer.
  • the amount of epoxy resin can be increased, a neutron shield having a high hydrogen content can be manufactured, and neutrons can be effectively shielded. That is, a neutron shield having both a neutron shielding ability and a line shielding ability can be manufactured.
  • the composition for a neutron shield according to the present invention is suitable for a composition for producing a neutron shield suitable for a cask for storing and transporting spent fuel.

Abstract

A cask, comprising a shell body (101) having, therein, a basket (130) formed of square pipes (132) or plate-like members forming cells (131) for storing spent fuel assemblies and a neutron shielding body formed by filling a composition (106) for the neutron shielding body containing a neutron shielding material formed mainly of macro-molecules, a refractory material, and a density increasing agent between the shell body (101) and an outer tube (105) installed on the outer periphery of the shell body.

Description

キャスク、 中性子遮蔽体用組成物、 及ぴ、 中性子遮蔽体製造法 Cask, composition for neutron shield, and method for producing neutron shield
技術分野 Technical field
• この発明は、 中性子遮蔽体用組成物に関し、 特に使用済燃料の貯蔵および運搬 用のキャスクに適した中性子遮蔽体製造用の組成物に関する。 また、 この中性子 明  The present invention relates to a composition for a neutron shield, and more particularly to a composition for manufacturing a neutron shield suitable for a cask for storing and transporting spent fuel. Also, this neutron
遮蔽体用組成物を用レ、たキャスクに関する。 書 The present invention relates to a cask using a composition for a shield. book
背景技術 Background art
近年の原子力産業の発展に伴い、 各種の原子力施設、 たとえば原子炉、 燃料再 処理工場などが各地に建設されているが、 これら各種の原子力施設などでは、 人 体が受ける放射線の量を極力低減し、 また放射線により構造材料や機器材料が損 傷しないようにしなければならない。 すなわち、 各種の原子力施設などの燃料あ るいは使用済み燃料 （リサイクル燃料とも言う） 力 ら発生する中性子は、 ェネル ギ一が高く、 強い透過力を有し、 他の物質と衝突すると γ線を発生して、 原子力 施設などの各種材料を損傷させることから、 この中性子おょぴッ線を安全確実に 遮蔽することができる中性子遮蔽体の開発が行なわれている。  With the development of the nuclear industry in recent years, various types of nuclear facilities, such as nuclear reactors and fuel reprocessing plants, have been constructed in various places.In these various types of nuclear facilities, the amount of radiation received by the human body has been reduced as much as possible. In addition, structural materials and equipment materials must not be damaged by radiation. In other words, the neutrons generated from the fuel or spent fuel (also called recycled fuel) of various nuclear facilities have high energy, have a high penetrating power, and emit gamma rays when colliding with other substances. Neutron shields that can safely and reliably shield this neutron penetration wire are being developed because they can generate and damage various materials such as nuclear facilities.
従来、 中性子遮蔽体としては、 コンクリートが用いられていたが、 このコンク リートは、 遮蔽壁としては相当の厚みを必要とし、 原子力船のように、 容積に制 限のある原子力施設では不適な中性子遮蔽体であり、 中性子遮蔽体の薄化が望ま れていた。  Conventionally, concrete has been used as a neutron shield, but this concrete requires a considerable thickness as a shielding wall and is unsuitable for nuclear facilities with a limited capacity, such as a nuclear ship. It is a shield, and the neutron shield needs to be thinner.
ここで、 中性子のうちの高速中性子は、 ほぼ同じ質量の水素元素と衝突するこ とによってエネルギーが吸収され、 効果的に減速される。 よって、 水素密度の高 レ、、すなわち水素含有率の高い物質が高速中性子の遮蔽に有効であり、例えば水、 パラフィン、 ポリエチレンなどを中性子遮蔽体として用いることができる。 この 水などの液体は、 コンクリートに比べて軽量であるが、 液体であるために取り扱 いが限定され、 さらには、 この水などの ί夜体を収納する容器自体の材質の中性子 遮蔽能が問題となる。 Here, fast neutrons among the neutrons are absorbed by elemental hydrogen of almost the same mass, so that energy is absorbed and decelerated effectively. Therefore, a substance having a high hydrogen density, that is, a substance having a high hydrogen content is effective for shielding fast neutrons. For example, water, paraffin, polyethylene, or the like can be used as the neutron shield. This liquid, such as water, is lighter than concrete, but it is In addition, the neutron shielding ability of the material of the container itself that stores the night body such as water is a problem.
そこで、 中性子の遮蔽については、 水素含有率の高いことから中性子の減速材 としての効果が大きい、 パラフィン、 ポリエチレンなどのポリオレフイン系熱可 塑性樹脂、 不飽和ポリエステル樹脂などの熱硬化性樹脂、 エポキシ樹脂等の樹脂 に、 中性子遮蔽材として微量のホウ素化合物とを配合したものが使われている。 一方、 γ線の遮蔽については、 中性子遮蔽体本体の外側を覆うような形状をもつ 線遮蔽用の構造物を配置して遮蔽している。  For shielding neutrons, the high hydrogen content has a great effect as a moderator for neutrons. Thermosetting resins such as polyolefin-based thermoplastic resins such as paraffin and polyethylene, unsaturated polyester resins, and epoxy resins A mixture of such a resin and a small amount of a boron compound as a neutron shielding material is used. On the other hand, gamma rays are shielded by arranging a ray shielding structure that covers the outside of the neutron shield body.
さらに、 万一、 火災が生じた場合でも、 ある程度以上の中性子遮蔽能を維持で きるような中性子遮蔽体の開発も行われている。 これについては耐火材として大 量の水酸化アルミニゥム粉末や水酸化マグネシゥム粉末等が配合された中性子遮 蔽体が提案されている （特開 2 0 0 1— 1 0 8 7 8 7号公報、 特許第 3 1 5 0 6 7 2号公報） ο  In addition, neutron shields have been developed that can maintain a certain level of neutron shielding ability even in the event of a fire. Regarding this, a neutron shielding body in which a large amount of aluminum hydroxide powder, magnesium hydroxide powder, or the like is blended as a refractory material has been proposed (Japanese Patent Application Laid-Open No. 2001-1088787, Patent No. 3 15 0 6 7 2) ο
しかしながら、 中性子の遮蔽においては、 中性子をより安全確実に遮蔽できる 中性子遮蔽体が求められている。 一方、 つ'.線の遮蔽においては、 現在主に使用さ れている樹脂等からなる中性子遮蔽体は、 比重が 0 . 9〜1 . 2と小さく、 高速 の中性子を遮蔽する際に発生する γ線を遮蔽するには適していなかつた。そこで、 中性子遮蔽体本体の外側に比重の大きレヽ材料を用いた γ線遮蔽用の構造物を配置 する必要があった。 つまり、 中性子遮蔽体自体で中性子遮蔽能と γ線の遮蔽を満 足させることはできていなかった。 However, there is a need for a neutron shield that can shield neutrons more safely and reliably. On the other hand, when shielding neutrons, the neutron shields made of resin, etc., which are currently mainly used, have a small specific gravity of 0.9 to 1.2, and are generated when high-speed neutrons are shielded. It is not suitable for shielding gamma rays. Therefore, it was necessary to arrange a gamma-ray shielding structure using a material with a large specific gravity outside the neutron shield body. In other words, the neutron shield itself could not satisfy the neutron shielding ability and the gamma ray shielding.
比重の大きレヽ材料を用いた γ線遮蔽用の構造物を中性子遮蔽体本体の外側に配 置しなければならないということは.、 容積の制限のある原子力施設等において、 最良の形態とは言えず、 中性子遮蔽能のみならず中性子遮蔽体自体の Ί線遮蔽能 の向上が期待されている。  The fact that a gamma-ray shielding structure using a material with a large specific gravity must be placed outside the neutron shield body is the best form for a nuclear facility with a limited volume. In addition, it is expected that not only the neutron shielding ability but also the neutron shielding body itself will improve the X-ray shielding ability.
耐火性にぉレ、ては、 水酸化アルミニゥムの脱水熱分解温度は、 2 4 5〜 3 2 0 °Cであり、 これに対して水酸ィヒマグネシウムの脱水熱分解温度は 3 4 0〜 3 9 0 °Cであるため耐火材としては水酸ィヒマグネシゥム粉末がより適していると考えら れる。 しカ し、 水酸化マグネシウム粉末を使用した場合、 組成物の粘度が上昇し て混練 ·充填に多大な時間と労力がかかるという問題点および樹脂内部に巻き込 まれたボイドが残留し、 中性子遮蔽能を低下させるおそれがあるという問題点が あった。 そのため、 実際にキャスク用に水酸ィ匕マグネシウム粉末が使用された例 はなく、また、水酸ィ匕マグネシウム粉末の粒径等についても検討された例もない。 本発明は、 上記に鑑みてなされたものであって、 中性子およびッ線を効果的に 遮蔽し、 耐火性に優れた中性子遮蔽体組成物およびそれを用いたキャスクを提供 することを目的とする。 さらに、 作業性のよい中性子遮蔽体組成物を提供するこ とも目的としている。 発明の開示 In terms of fire resistance, the dehydration and thermal decomposition temperature of aluminum hydroxide is 245 ° C to 320 ° C, whereas the dehydration and thermal decomposition temperature of magnesium hydroxide is 340 ° C. Since the temperature is 390 ° C, it is considered that hydroxy-magnesium powder is more suitable as a refractory material. It is. However, when magnesium hydroxide powder is used, the viscosity of the composition increases, and it takes a lot of time and effort for kneading and filling.Voids trapped inside the resin remain, and neutron shielding occurs. There is a problem that performance may be reduced. Therefore, there is no example in which the magnesium hydroxide powder was actually used for the cask, and there was no example in which the particle size of the magnesium hydroxide was examined. The present invention has been made in view of the above, and has as its object to provide a neutron shielding composition excellent in fire resistance, which effectively shields neutrons and wires, and a cask using the same. . Another object is to provide a neutron shielding composition having good workability. Disclosure of the invention
本発明の目的は、 少なくとも上述の課題を解決するものである。  An object of the present invention is to solve at least the above-mentioned problems.
本発明のキャスクは、 使用済み燃料集合体を収容するセルを構成する角パイプ 又は板状部材からなるバスケットを内部に有する胴本体と、 前記胴本体とその外 周に設けられた外筒との間に、高分子を主体とした中性子遮蔽材料と、耐火材と、 密度増加剤とを含有する中性子遮蔽体用組成物を充填してなる中性子遮蔽体とを 有することを特徴とする。  A cask of the present invention comprises: a trunk body having a basket formed of a square pipe or a plate-like member constituting a cell for storing a spent fuel assembly; and a trunk body and an outer cylinder provided on an outer periphery thereof. It is characterized by having a neutron shield filled with a neutron shield composition containing a neutron shielding material mainly composed of a polymer, a refractory material and a density increasing agent.
本発明のキャスクは、 使用済み燃料集合体を収容するセルを構成する角パイプ 又は板状部材からなるバスケットを内部に有する胴本体と、 前記胴本体とその外 周に設けられた外筒との間に、高分子を主体とした中性子遮蔽材料と、粒径が 1 . 5〜 1 5 μ mの水酸化マグネシゥム粉末とを含有する中性子遮蔽体用組成物を充 填してなる中性子遮蔽体とを有することを特徴とする。  A cask of the present invention comprises: a trunk body having a basket formed of a square pipe or a plate-like member constituting a cell for storing a spent fuel assembly; and a trunk body and an outer cylinder provided on an outer periphery thereof. In between, a neutron shield filled with a neutron shield composition containing a neutron shield material mainly composed of a polymer and magnesium hydroxide powder having a particle size of 1.5 to 15 μm. It is characterized by having.
本発明の中性子遮蔽体用組成物は、 キャスクに適した中性子遮蔽体製造用の組 成物であって、 高分子を主体とした中性子遮蔽材料と、 粒径が 1 . 5〜 1 5 μ m の水酸化マグネシゥム粉末とを含有することを特徴とする。  The composition for a neutron shield of the present invention is a composition for producing a neutron shield suitable for a cask, and a neutron shielding material mainly composed of a polymer and a particle size of 1.5 to 15 μm. And magnesium hydroxide powder.
本発明の中性子遮蔽体用組成物は、 キャスクに適した中性子遮蔽体製造用の組 成物であって、 高分子を主体とした中性子遮蔽材料と、 耐火材と、 密度増加剤と を含有することを特徴とする。 The composition for a neutron shield of the present invention is a composition for producing a neutron shield suitable for a cask, and includes a neutron shielding material mainly composed of a polymer, a refractory material, and a density increasing agent. It is characterized by containing.
本発明の中性子遮蔽体用組成物は、 キャスクに適した中性子遮蔽体製造用の組 成物であって、 高分子を主体とした中性子遮蔽材料を 2 0〜5 5質量。 /0と、 前記 硬化剤を 4〜 5 5質量％と、 前記耐火材を 5〜 6 0質量％と、 前記密度増加剤を 5〜 4 0質量％と、 ホウ素化合物を 0 . 5〜 1 0質量％とを含有することを特徴 とする。 The neutron shielding composition of the present invention is a composition for producing a neutron shielding suitable for a cask, and contains 20 to 55 mass of a neutron shielding material mainly composed of a polymer. / 0 , 4 to 55% by mass of the curing agent, 5 to 60% by mass of the refractory material, 5 to 40% by mass of the density increasing agent, and 0.5 to 10% of the boron compound. % By mass.
本発明の中性子遮蔽体製造法は、 構成成分として高分子を主体とした中性子遮 蔽材料を含有し、 γ線の遮蔽性能を維持しつつ、 中性子遮蔽効果を上げることが できる中性子遮蔽体の製造法であって、 前記高分子を主体とした中性子遮蔽材料 以外の構成成分を密度増加剤で置換することにより、 中性子遮蔽体用組成物の比 ' 重を 1 . 6 2〜1 . 7 2 g / c m3に維持することを特徴とする。 The method for producing a neutron shield of the present invention comprises producing a neutron shield which contains a neutron shielding material mainly composed of a polymer as a constituent component and can enhance the neutron shielding effect while maintaining the γ-ray shielding performance. A neutron shielding composition by replacing a component other than the polymer-based neutron shielding material with a density-increasing agent, thereby increasing the specific gravity of the neutron shielding composition to 1.62 to 1.72 g. and maintains the / cm 3.
以上述べたことと、 本発明のその他の目的、 特徴、 利点を、 以下の発明の詳細 な説明力 ら明ら力 こする。 ' ' . 図面の簡単な説明  The foregoing and other objects, features, and advantages of the present invention will be apparent from the following detailed description of the invention. ''. Brief description of the drawing
第 1図は、 本発明による中性子遮蔽体用組成物の一実施の形態を示す概念図で あり、 第 2図は、 本発明による中性子遮蔽体用組成物における密度増加剤と水素 含有量との関係を示す特性図であり、 第 3図は、 本発明による密度増加剤の密度 と中性子遮蔽体の外側の中性子線 +二次 γ線量相対比との関係を示す特性図であ り、 第 4図は、 この発明に適用されるキャスクの構成を示す斜視図であり、 第 5 図は、 図 4に示したキャスクの構成を示す軸方向断面図であり、 第 6図は、 図 4 に示したキャスクの構成を示す径方向断面図であり、 +第 7図は、 板状部材からな るバスケットを内部に有する胴本体を有するキャスクの概要を示す説明図であり、 第 8図は、 耐火試験容器を示した図である。 発明を実施するための最良の形態  FIG. 1 is a conceptual diagram showing one embodiment of the neutron shielding composition according to the present invention, and FIG. 2 is a graph showing the relationship between the density increasing agent and the hydrogen content in the neutron shielding composition according to the present invention. FIG. 3 is a characteristic diagram showing the relationship between the density of the density-increasing agent according to the present invention and the relative ratio of neutron beam + secondary γ dose outside the neutron shield. FIG. 5 is a perspective view showing a configuration of a cask applied to the present invention. FIG. 5 is an axial cross-sectional view showing a configuration of the cask shown in FIG. 4, and FIG. 6 is a diagram shown in FIG. FIG. 7 is an explanatory view showing an outline of a cask having a trunk body having a basket formed of a plate-like member inside, and FIG. 8 is a fireproof FIG. 3 is a view showing a test container. BEST MODE FOR CARRYING OUT THE INVENTION
以下に、 本発明の実施の形態を詳細に説明する。 なお、 この実施の形態により 本発明が限定されるものではない。 なお、 本明細書および図面において、 「中性 子遮蔽体用糸且成物」 と 「レジン」 とは同義である。 Hereinafter, embodiments of the present invention will be described in detail. In addition, according to this embodiment, The present invention is not limited. In the present specification and the drawings, the terms “thread for neutron shield” and “resin” are synonymous.
( I ) 中性子遮蔽体用組成物  (I) neutron shielding composition
まず、 本発明の中性子遮蔽体用組成物について説明する。 中性子遮蔽体用組成 物は、 基本成分として、 主剤としての高分子を主体とした中性子遮蔽材料、 硬化 剤、 ホウ素化合物が混合されたものである。 この基本成分に耐火材を混合するこ とにより難燃性を付与することができる。また、カーボン粉末、および zまたは、 密度増加剤を混合することにより Y線遮蔽能、 中性子遮蔽能、 作業性等をより向 上させることができる。 以下、 各成分について詳細に説明するが、 特に断らない 限り市販のものを使用することができる。  First, the neutron shielding composition of the present invention will be described. The composition for a neutron shielding body is a mixture of a neutron shielding material mainly composed of a polymer as a main component, a curing agent, and a boron compound as basic components. Flame retardancy can be imparted by mixing a refractory material with this basic component. Further, by mixing carbon powder and z or a density increasing agent, the Y-ray shielding ability, neutron shielding ability, workability, and the like can be further improved. Hereinafter, each component will be described in detail, but a commercially available component can be used unless otherwise specified.
( i ) '高分子を主体とした中性子遮蔽材料  (i) 'A neutron shielding material mainly composed of polymer
高分子を主体とした中性子遮蔽材料としては、 例えばポリエチレン、 ポリプロ ピレン、 ポリプチレン等のポリオレフイン系樹脂、 およびエポキシ樹脂等が、 代 表的なものとして挙げられる。 エポキシ樹脂とは、 架橋し得るエポキシ基を含む 樹脂を意味する。  Typical examples of the neutron shielding material mainly composed of a polymer include a polyolefin resin such as polyethylene, polypropylene, and polyethylene, and an epoxy resin. Epoxy resin means a resin containing a crosslinkable epoxy group.
エポキシ樹脂としては、 例えばグリシジルエーテル型/ 2官能フエノ一ル型ェ ポキシ樹脂、 グリシジルエーテル型/多官能フエノール型エポキシ樹脂、 グリシ ジルエーテル型/アルコール型ェポキシ樹脂、 グリシジルェステル型ェポキシ樹 脂、脂肪族エポキシ樹脂、脂環族エポキシ樹脂、変性エポキシ樹脂等が挙げられ、 さらにこれらのエポキシ樹脂の環構造に水素を添カ卩した水素添加エポキシ樹脂等 も挙げられる。 中でも水素添加エポキシ樹脂が好ましい。 エポキシ樹脂は、 1種 類のエポキシ樹脂を用いても、 2種以上のエポキシ樹脂を混合して用いてもよレ、。 さらに、 エポキシ樹脂の具体例を挙げると、 ダリシジルエーテル型/ 2官能フ ェノ一ル型ェポキシ樹脂としては、 ビスフエノ一ノレ型ェポキシ樹脂、 スチルべン 型エポキシ樹脂、 ビフエニル型エポキシ樹脂、 単環型芳香族エポキシ樹脂、 縮合 多環型芳香族ェポキシ樹脂等、 グリシジルエーテル型/多官能フエノ一ル型ェポ キシ樹脂としては、 ポリフエノール型エポキシ樹脂、 フエノールノボラック型ェ ポキシ樹脂、 メチレン基置換型フエノールノボラック型エポキシ樹脂、 アルキレ ン変性フエノールノポラック型ェポキシ樹脂、 ァラルキル変性フエノールノボラ ック型エポキシ樹脂等、 脂肪族エポキシ樹脂'としては、 直接酸ィヒによる脂環式ェ ポキシ樹脂、 官能基のグリシジルエーテル化による脂環式エポキシ樹脂、 ジクロ 口ペンタジェン型エポキシ樹脂、 鎖上脂肪族エポキシ樹脂等、 変性エポキシ樹脂 としては、 シリコーン変性エポキシ樹脂、 ウレタン変性エポキシ樹脂、 ポリイミ ドおよびポリアミド変性エポキシ樹脂、 光硬化性エポキシ樹脂等、 その他には、 リン含有エポキシ樹脂、 硫黄含有エポキシ樹脂、 窒素含有エポキシ樹脂等が挙げ られる。 水素添加エポキシ樹脂としては、 水素添加ビスフエノール A型エポキシ 樹脂、 水素添カ卩ビスフエノール F型エポキシ樹脂、 ノボラック型グリシジルエー テル樹脂を水素添加した樹脂等が挙げられる。 Epoxy resins include, for example, glycidyl ether type / bifunctional phenol type epoxy resin, glycidyl ether type / polyfunctional phenol type epoxy resin, glycidyl ether type / alcohol type epoxy resin, glycidyl ester type epoxy resin, fat Group epoxy resins, alicyclic epoxy resins, modified epoxy resins, and the like. Further, hydrogenated epoxy resins obtained by adding hydrogen to the ring structure of these epoxy resins, and the like are also included. Among them, a hydrogenated epoxy resin is preferable. The epoxy resin may be a single type of epoxy resin or a mixture of two or more types of epoxy resins. Furthermore, specific examples of epoxy resins include, as dalicidyl ether type / bifunctional phenol type epoxy resins, bisphenol mono type epoxy resins, stilbene type epoxy resins, biphenyl type epoxy resins, and monocyclic epoxy resins. Glycidyl ether / polyfunctional phenolic epoxy resins, such as polyaromatic epoxy resins and condensed polycyclic aromatic epoxy resins, include polyphenol epoxy resins and phenol novolak resins. Aliphatic epoxy resins such as epoxy resins, methylene group-substituted phenol novolak epoxy resins, alkylene-modified phenol novolak epoxy resins, aralkyl-modified phenol novolak epoxy resins, etc. Modified epoxy resins such as formula epoxy resins, alicyclic epoxy resins by glycidyl etherification of functional groups, cyclopentagon-type epoxy resins, and chain-chain aliphatic epoxy resins include silicone-modified epoxy resins, urethane-modified epoxy resins, and polyimidines. And a polyamide-modified epoxy resin, a photocurable epoxy resin, and the like, and other examples include a phosphorus-containing epoxy resin, a sulfur-containing epoxy resin, and a nitrogen-containing epoxy resin. Examples of the hydrogenated epoxy resin include a hydrogenated bisphenol A-type epoxy resin, a hydrogenated potassium bisphenol F-type epoxy resin, and a resin obtained by hydrogenating a novolak-type glycidyl ether resin.
水素添加されていないェポキシ樹 '脂のうち好ましくはビスフエノール型ェポキ シ樹脂、 脂肪族エポキシ樹脂である。 特に好ましくは水素添加したエポキシ樹脂 であり、 ビスフエノール型エポキシ樹脂の環構造に水素を添加した水素添加ビス フエノール A型ェポキシ樹脂である。 水素添加ビスフエノール A型エポキシ樹脂 のような水素含有量の大きい水素添加エポキシ樹脂を用いることにより、 中性子 遮蔽能のより優れた中性子遮蔽体を製造することが可能となる。  Of the non-hydrogenated epoxy resins, bisphenol-type epoxy resins and aliphatic epoxy resins are preferred. Particularly preferred is a hydrogenated epoxy resin, and a hydrogenated bisphenol A type epoxy resin obtained by adding hydrogen to the ring structure of a bisphenol type epoxy resin. By using a hydrogenated epoxy resin having a large hydrogen content such as a hydrogenated bisphenol A-type epoxy resin, it becomes possible to manufacture a neutron shield having better neutron shielding ability.
Figure imgf000008_0001
Figure imgf000008_0001
水素添加ビスフエノ一ル A型エポキシ樹脂 上記水素添加ビスフヱノール A型ェポキシ樹脂の構造式中の nの好ましい範囲 は、 n = 0〜2であり、 n = 0〜0 . 1程度がより好ましい。  Hydrogenated bisphenol A type epoxy resin The preferable range of n in the structural formula of the hydrogenated bisphenol A type epoxy resin is n = 0 to 2, and more preferably n = 0 to 0.1.
高分子を主体とした中性子遮蔽材料の含有量は、 用いる材料、 他の成分の種類 や含有量等によつて変動するため、 規定することは困難である力 例えば組成物 全体中、 2 0〜 5 5質.量％、 好ましくは 2 4〜 4 7質量％、 特に好ましくは 3 5 〜4 2質量％である。 2 0質量％未満であると中性子遮蔽能が弱くなる傾向があ り、 5 5質量0 /0を超えると他の成分とのパランスが良くないためである。 The content of the neutron shielding material mainly composed of polymer fluctuates depending on the material used, the type and content of other components, etc., so it is difficult to specify the force. In the whole, it is 20 to 55 mass%, preferably 24 to 47 mass%, and particularly preferably 35 to 42 mass%. 2 0 is less than mass% be prone neutron shielding ability is weakened, because when it exceeds 5 5 mass 0/0 poor Palance with other components.
( i i ) 硬化剤  (ii) Curing agent
硬化剤は、 高分子を主体とした中性子遮蔽材料の種類によって、 適したものが 選択される。 具体的には、 エポキシ樹脂と反応して架橋構造を形成する硬化剤と しては、 例えばアミン系硬化剤、 酸および酸無水物系硬化剤、 フエノール系硬化 剤等が挙げられ、 好ましくはァミン系硬化剤が用いられる。 さらにアミン系硬化 剤のうち、 脂環式ァミン系硬化剤、 芳香族ァミン系硬化剤等の環構造を有する硬 ィ匕剤は、 耐熱性が高いため、 本発明の組成物に好適に用いられる。 硬化剤は、 1 種類の硬化剤を用いても、 2種以上の硬化剤を混合して用いてもよレ、。  A suitable curing agent is selected depending on the type of neutron shielding material mainly composed of a polymer. Specifically, examples of the curing agent that reacts with the epoxy resin to form a crosslinked structure include amine-based curing agents, acids and acid anhydride-based curing agents, phenol-based curing agents, and the like. A system curing agent is used. Further, among amine-based curing agents, sclerosing agents having a ring structure such as alicyclic amine-based curing agents and aromatic amine-based curing agents are preferably used in the composition of the present invention because of their high heat resistance. . The curing agent may be a single curing agent or a mixture of two or more curing agents.
硬化剤の好ましい添加量は、 用いられる硬化剤の種類、 他の成分の種類や含有 量等によって変動するため、 規定することは困難であるが、 ァミン系硬化剤の一 例を挙げると、組成物全体中、 4〜 5 5質量％、好ましくは 4 . 5〜 3 0質量％、 特に好ましくは 6〜 1 5質量％である。 4質量 °/0未満であると硬化剤としての効 果が弱く、 5 5質量％を超えると硬ィ匕が早くなりすぎ、 充填等に必要な作業時間 を確保できない。 It is difficult to specify the preferred amount of the curing agent because it varies depending on the type of the curing agent used, the type and content of other components, and the like. It is 4 to 55% by mass, preferably 4.5 to 30% by mass, particularly preferably 6 to 15% by mass in the whole product. When the amount is less than 4% by mass / 0 , the effect as a curing agent is weak, and when the amount exceeds 55% by mass, hardening becomes too fast, and the working time required for filling or the like cannot be secured.
( i i i ) 耐火材  (i i i) Refractory
耐火お-とは、 例えば火災が生じた場合のように中性子遮蔽体が高温にさらされ たときに、 ある程度以上の中性子遮蔽能を維持できるよう中性子遮蔽体を残存さ せることを目的として加えられるものであり、 例えば水酸化アルミ-ゥム、 水酸 化マグネシウム等の化合物をいう。 水酸化マグネシウムの脱水分解温度は、 3 4 0〜3 9 0 °Cで水酸ィ匕アルミニウムの脱水分解温度より高温であるため耐火材と して特に適している。  Fireproofing is added to keep the neutron shield so that it can maintain a certain level of neutron shielding capacity when the neutron shield is exposed to high temperatures, for example, when a fire occurs. And compounds such as aluminum hydroxide and magnesium hydroxide. Magnesium hydroxide has a dehydration decomposition temperature of 340 ° C. to 390 ° C., which is higher than the dehydration decomposition temperature of hydroxide aluminum, so that it is particularly suitable as a refractory material.
一般的に、 水酸化マグネシウムは、 粉末状になっている。 この水酸化マグネシ ゥム粉末の粒径については、 通常は特に調整されていなレ、。 粒径を調整すること により、 中性子遮蔽体用組成物としてより好適な組成物となる。 耐火材として水酸化マグネシウム粉末を用いる場合、 好ましい水酸化マグネシ ゥム粉末の粒径は、 1 . 5〜 1 5 mであり、 特に 1 . 5〜 5 μ mの粒径が好まし レ、。 これらの粒径を有す水酸ィヒマグネシウム粉末は、 巿販のものを用いることが できる。 ここで、水酸化マグネシウム粉末の粒径は、全ての粉末の粒径が 1 . 5〜 1 5 μ mの範囲にあること 望ましいが、 現実的には水酸化マグネシウム粉末の 8 0 %以上が 1 . 5〜 1 5 mの範囲にあればよく、好ましくは 9 0 °/0以上、特に 好ましくは 9 5 %以上が当該範囲にあることが望ましい。粒径 1 . 5 μ πι未満の水 酸化マグネシウム粉末を用いて、 水酸ィ匕マグネシウム粉末の混合比をあげると粘 '度が上昇して混練 ·充填に多大な時間と労力がかかってしまう。 従って、 水酸ィヒ マグネシウム粉末の混合比を低く抑えることになるため、 耐火性が悪くなる。 他 方、 粒径 1 5 i mを超えた水酸化マグネシウム粉末を用いた場合、 水酸化マグネ シゥム粉末の総表面積が小さくなるため耐火性が低下するおそれがある。 すなわ ち、 1 . 5 - 1 5 μ mの水酸化マグネシゥム粉末を用レ、ることにより、耐火性を維 持しつつ、 混練 ·充填に多大な時間と労力がかからない作業性のよい中性子遮蔽 体組成物を得ることができる。 Generally, magnesium hydroxide is in powder form. The particle size of the magnesium hydroxide powder is not usually adjusted. By adjusting the particle size, the composition becomes more suitable as a composition for a neutron shield. When magnesium hydroxide powder is used as the refractory material, the preferred particle size of the magnesium hydroxide powder is 1.5 to 15 m, and particularly preferably 1.5 to 5 μm. Commercially available magnesium hydroxide powder having these particle sizes can be used. Here, the particle size of the magnesium hydroxide powder is desirably such that the particle size of all the powders is in the range of 1.5 to 15 μm, but in reality, 80% or more of the magnesium hydroxide powder is 1%. It may be in the range of 5 to 15 m, preferably 90 ° / 0 or more, particularly preferably 95% or more. If magnesium hydroxide powder having a particle size of less than 1.5 μπι is used and the mixing ratio of magnesium hydroxide powder is increased, the viscosity increases and a great deal of time and effort is required for kneading and filling. Therefore, the mixing ratio of magnesium hydroxide powder is kept low, and the fire resistance deteriorates. On the other hand, when magnesium hydroxide powder having a particle size of more than 15 im is used, the total surface area of the magnesium hydroxide powder becomes small, so that fire resistance may be reduced. In other words, by using 1.5-15 μm magnesium hydroxide powder, neutron shielding with good workability that does not require much time and labor for kneading and filling while maintaining fire resistance A body composition can be obtained.
さらに中性子遮蔽能の観点から具体的に説明すると、 硬化前エポキシ樹脂の容 .器への流し込みに際し、 空隙部をなくすため、 硬化前レジンの粘度は 1 0 O P a • s以下にすることが望ましい。 1 . 5 μ m未満の水酸化マグネシゥム粉末を用レ、 た場合、 粘度を適正に保つには水酸化マグネシゥム粉末の混入量は 3 0質量％以 下となり、 溶融栓付き密閉容器内で耐火条件温度 （外部 8 0 0 °C、 3 0分） とす ると、樹脂内部にボイドが発生し、中性子遮蔽能が低下するおそれがある。他方、 1 5 μ mを超えた水酸化マグネシウム粉末を用いた場合、 水酸化マグネシウム粉 末の混入量は 5 0質量％以上とすることができるが、 水酸化マグネシウム粉末の 表面積が低下するため、 耐火条件温度 （外部 8 0 0 °C、 3 0分） で樹脂内部にボ ィドが発生し、 中性子遮蔽能が低下するおそれがある。  More specifically, from the viewpoint of neutron shielding ability, it is desirable that the viscosity of the resin before curing be 10 OPa • s or less in order to eliminate voids when pouring the epoxy resin before curing into a container. . When using magnesium hydroxide powder with a particle size of less than 1.5 μm, the amount of magnesium hydroxide powder should be less than 30% by mass to maintain proper viscosity. At the temperature (800 ° C for 30 minutes), voids may be generated inside the resin and the neutron shielding ability may be reduced. On the other hand, when magnesium hydroxide powder exceeding 15 μm is used, the mixing amount of magnesium hydroxide powder can be 50% by mass or more, but since the surface area of magnesium hydroxide powder decreases, At the refractory temperature (outside 800 ° C, 30 minutes), voids may be generated inside the resin and the neutron shielding ability may be reduced.
つまり、水酸化マグネシウム粉末の粒径を 1 . 5〜 1 5 μ mにすることにより耐 火性および中性子遮蔽能がより優れた中性子遮蔽体を得ることができる。 また、 作業性も向上する。 That is, by setting the particle size of the magnesium hydroxide powder to 1.5 to 15 μm, a neutron shield having more excellent fire resistance and neutron shielding ability can be obtained. Also, Workability is also improved.
一方、 水酸化アルミニゥムは、 水素含有量の点から水酸ィヒマグネシゥムより優 れているので、 水酸化アルミニゥム粉末と水酸化マグネシゥム粉末とを適宜混合 して耐火材としてもよい。 その場合用いる水酸ィ匕アルミニウム粉末は、 0. 07 質量％以下の低ソーダ分の水酸ィ匕アルミニウム粉末を用いることが好ましい。 ソ ーダ分 （Na2〇） を 0. 07質量％以下にすることによって、 150°C以上まで 水素含有率を保持することができる。 また、 水酸ィヒアルミニウム粉末、 水酸化マ グネシゥム粉末以外の耐火材をさらに添加したものであってもよい。 On the other hand, since aluminum hydroxide is superior to hydroxymagnesium in terms of hydrogen content, aluminum hydroxide powder and magnesium hydroxide powder may be appropriately mixed to form a refractory material. In this case, it is preferable to use aluminum hydroxide powder having a low soda content of 0.07% by mass or less. By setting the soda content (Na 2 〇) to 0.07 mass% or less, the hydrogen content can be maintained up to 150 ° C or more. Further, a refractory material other than aluminum hydroxide powder and magnesium hydroxide powder may be further added.
耐火材の添加量は、 用いられる耐火材、 他の成分の種類や含有量等によって変 動するため、 規定することは困難であるが、 組成物全体中、 好ましくは 5〜 60 質量％、 特に好ましくは 33〜41質量％である。 5質量％未満だと »火材とし ての効果が弱く、 60質量％を超えると高分子を主体とした中性子遮蔽材料等の 割合が小さくなり、 中性子吸収能を小さくするためである。  It is difficult to define the amount of the refractory material to be added because it varies depending on the type of refractory material used, the type and content of other components, etc., but it is preferably 5 to 60% by mass, particularly Preferably it is 33 to 41% by mass. If it is less than 5% by mass, the effect as a fire material is weak, and if it exceeds 60% by mass, the proportion of neutron shielding materials, etc. mainly composed of polymers becomes small, and the neutron absorption capacity is reduced.
( i V) 密度増加剤  (i V) Density increasing agent
密度増加剤は、 密度の高い材料であり、 中性子遮蔽体の比重を大きくすること ができれば、 他の成分に悪影響を与えない限りいかなる材料でもよい。 ここで、 y線を効果的に遮蔽する密度増加剤自体の密度は、 5. 0 g/cm3以上、好まし くは 5. 0〜22. 5
Figure imgf000011_0001
より好ましくは 6.0〜 1 5 g / c m3である。 5. 0 g/c m3未満であると中性子遮蔽能を損なわずに γ線を効果的に遮蔽する のは難しく、 22. 5 g/cm3を超えると添カ卩量に応じた効果が認められない。 具体的には、金属粉または金属の酸ィ匕物粉等が挙げられる。密度増加剤として、 好ましくは、 融点が 350°C以上の金属である C r、 Mn、 F e、 N i、 Cu、 S b、 B i、 U、 W等、 および/または、 融点が 1000°C以上の金属の酸ィ匕物 である N i O、 Cu〇、 ZnO、 Z r 02、 SnO、 Sn〇2、 W〇2、 U〇2、 P b 0、 W03、 ランタノイド酸化物等が挙げられ 6。 中でも Cu、 W02、 W〇3、 Z r〇2、 Ce〇2が特に好ましい。 コスト面で利点を有するためである。 密度増加 剤は、 1種類で用いても、 2種以上を混合して用いてもよい。 ■ 粒径は特に限定はされないが、 粒径が大きいと密度増加剤が、 製造中に沈降す る恐れがあるので沈降しない程度で小さな来立径が好ましレ、。 沈降しない粒径につ いては、 その他の条件 （例えば、 組成物の温度、 粘度、 硬化速度等） によって大 きく作用されるため、 単純に数値で規定できない。 The density enhancer is a high-density material, and any material can be used as long as the specific gravity of the neutron shield can be increased, as long as it does not adversely affect other components. Here, the density of the density-increasing agent itself that effectively blocks y-rays is 5.0 g / cm 3 or more, preferably 5.0 to 22.5.
Figure imgf000011_0001
More preferably 6.0~ 1 5 g / cm 3. If it is less than 5.0 g / cm 3 , it is difficult to effectively shield γ-rays without impairing the neutron shielding ability, and if it exceeds 22.5 g / cm 3 , the effect according to the amount of added syrup is recognized. I can't. Specifically, a metal powder or a metal sardine powder may be used. As the density increasing agent, preferably, a metal having a melting point of 350 ° C or more, such as Cr, Mn, Fe, Ni, Cu, Sb, Bi, U, W, and / or a melting point of 1000 ° N i O a Sani匕物of C or more metals, Cu_〇, ZnO, Z r 0 2, SnO, Sn_〇 2, W_〇 2, U_〇 2, P b 0, W0 3, lanthanoid oxides 6. Among them Cu, W0 2, W_〇 3, Z R_〇 2, Ce_〇 2 is particularly preferred. This is because it has an advantage in cost. The density increasing agent may be used singly or as a mixture of two or more. ■ The particle size is not particularly limited, but if the particle size is large, the density increasing agent may settle during production. The particle size that does not settle cannot be simply specified by a numerical value because it is largely affected by other conditions (eg, the temperature, viscosity, curing rate, etc. of the composition).
密度増加剤を添加することにより、 中' I生子遮蔽体の比重を上げることができ、 線をより効果的に遮蔽することができる。 また、 上記の金属粉や金属の酸化物 粉を用いることで耐火性も向上させることができる。  By adding the density increasing agent, the specific gravity of the middle-I viable shield can be increased, and the line can be more effectively shielded. In addition, the use of the above metal powder or metal oxide powder can improve the fire resistance.
また、 高分子を主体としだ中性子遮蔽材料以外の添加物の一部、 主として耐火 材の一部を密度増加剤で置換することによって、 水素含有量を増加させることが できる。 主として耐火材の一部と一部置換を行なうことにより、 中性子遮蔽体用 組成物の比重を維持 ( 1 . 6 2 ~ 1 . 7 2 g / c m3) しながら、 エポキシ樹脂の量 を多くすることができるため水素含有量の高い中性子遮蔽体を製造することがで き、 効果的に中性子を遮蔽することができる。 すなわち、 中性子遮蔽能と τ/線の 遮蔽とを両立することが可能となる。 Also, the hydrogen content can be increased by replacing some of the additives other than the neutron shielding material mainly composed of polymers, mainly some of the refractory materials, with a density increasing agent. Primarily by performing some of the refractory material and the partially substituted while maintaining the specific gravity of the neutron shielding-body composition (1. 6 2 ~ 1. 7 2 g / cm 3), to increase the amount of the epoxy resin Therefore, a neutron shield having a high hydrogen content can be manufactured, and neutrons can be effectively shielded. In other words, it is possible to achieve both neutron shielding ability and τ / ray shielding.
混合する密度増加剤の添加量は、上記中性子遮蔽体用組成物の比重（ 1 . 6 2〜 1 . 7 2 g / c m3) を保つように適宜調節して添加することができる。 具体的に は、 用レヽられる密度増加剤の種類、 他の成分の種類や含有量等によつて変動する ため、 規定することは困難であるが、 例えば組成物全体中、 5〜4 0質量％、 好 ましくは 9〜 3 5質量。 /0である。 C e 02を用いる場合は、 1 5〜 2 0質量％が特 に好ましい。 5質量。/。未満では添加の効果が認められにくく、 4 0質量％を超え ると組成物の比重を 1 . 6 2〜1 . 7 2 g / c m3の範囲に保つことが困難となる。 ここで、 更に図面を用いて密度増加剤を用いた実施の形態の具体例について詳 細に説明する。 The amount of the density increasing agent to be mixed can be appropriately adjusted and added so as to maintain the specific gravity (1.62 to 1.72 g / cm 3 ) of the neutron shielding composition. Specifically, it is difficult to specify because it varies depending on the type of density increasing agent used, the type and content of other components, etc., for example, 5 to 40 mass% in the whole composition %, Preferably 9 to 35 mass. / 0 . When using the C e 0 2, 1 5~ 2 0 % by mass, especially. 5 mass. /. When the amount is less than 40% by mass, it is difficult to maintain the specific gravity of the composition in the range of 1.62 to 1.72 g / cm 3 . Here, a specific example of an embodiment using a density increasing agent will be described in detail with reference to the drawings.
(第 1の実施の形態）  (First Embodiment)
第 1図は、 本実施の形態による中性子遮蔽体の構成例を示す概念図である。 な お、 図中の斜線部分は、 水素量を模式的に示している。  FIG. 1 is a conceptual diagram showing a configuration example of a neutron shield according to the present embodiment. The hatched portion in the figure schematically shows the amount of hydrogen.
すなわち、 本実施の形態による中性子遮蔽体は、 第 1図に示すように、 高分子 を主体とした中性子遮蔽材料 1に、 耐火材 2と、 当該耐火材 2よりも密度が高い 密度増加剤 3とを混合したものである。 That is, as shown in FIG. 1, the neutron shield according to the present embodiment is a polymer This is a mixture of a neutron shielding material 1 mainly composed of a refractory material 2 and a density increasing agent 3 having a higher density than the refractory material 2.
ここで、 特に密度増加剤 3としては、 金属粉あるいは金属の酸化物粉を混合し たりすることにより、 材料の密度を維持しながら （1.62〜； 1. 72gZmLの 範囲） '水素含有量を上げた中性子遮蔽体としている。  Here, in particular, as the density increasing agent 3, by mixing metal powder or metal oxide powder, the density of hydrogen is maintained while maintaining the density of the material (from 1.62 to 1.72 gZmL). Neutron shield.
また、 混合する密度増加剤 3の密度は、 5. Og/mL以上、 好ましくは 5.0 〜22. 5g/mL、 より好ましくは 6.0〜15gZmLである。  The density of the density increasing agent 3 to be mixed is at least 5. Og / mL, preferably 5.0 to 22.5 g / mL, and more preferably 6.0 to 15 gZmL.
さらに、 密度増加剤 3としては、 融点が 350°C以上の金属粉あるいは融点が 1000 °c以上の金属の酸化物粉を混合することが好ましい。  Further, as the density increasing agent 3, it is preferable to mix a metal powder having a melting point of 350 ° C or more or an oxide powder of a metal having a melting point of 1000 ° C or more.
これらに該当する粉体の材料として、 金属では、 例えば Cr、 Mn、 Fe、 Ni、 Cu、 Sb、 Bi、 U、 W等が挙げられる。  Examples of powder materials corresponding to these include metals such as Cr, Mn, Fe, Ni, Cu, Sb, Bi, U, and W.
また、 金属の酸化物では、 例えば NiO、 CuO、 Z nO、 Zr〇2、 SnO、 S n〇2、 W02、 Ce〇2、 U02、 P b 0、 P b 0、 W03等が挙げられる。 In an oxide of a metal, like for example NiO, CuO, Z nO, Zr_〇 2, SnO, S N_〇 2, W0 2, Ce_〇 2, U0 2, P b 0 , P b 0, W0 3 and the like Can be
なお、 高分子を主体とした中性子遮蔽材料 1としては、 例えばポリエチレン、 ポリプロピレン、 ポリブチレン等のポリオレフイン系樹脂、 およびエポキシ樹脂 等が、 代表的なものとして挙げられる。  The neutron shielding material 1 mainly composed of a polymer includes, for example, polyolefin-based resins such as polyethylene, polypropylene, and polybutylene, and epoxy resins.
次に、 以上のように構成した本実施の形態による中性子遮蔽体においては、 高 分子を主体とした中性子遮蔽材料 (樹脂) 1に、 耐火材 2と、 当該耐火材 2より も密度が高い密度増加剤 3を混合させたことにより、 密度を一定の値に維持しな がら （1.62〜1. 72g/mLの範囲） 、 水素含有量を増加させることができ る。  Next, in the neutron shielding body according to the present embodiment configured as described above, the neutron shielding material (resin) 1 mainly composed of a high molecule is provided with a refractory material 2 and a density higher than the refractory material 2. By mixing the increasing agent 3, the hydrogen content can be increased while maintaining the density at a constant value (in the range of 1.62 to 1.72 g / mL).
すなわち、 耐火材 2は、 中性子遮蔽材料 1よりも密度がやや高く、 やや少ない 水素を含有する。  That is, the refractory material 2 has a slightly higher density than the neutron shielding material 1 and contains slightly less hydrogen.
そこで、 耐火材 2の一部を、 水素を含まない密度増加剤 3で置き換え、 密度が 同等となるようにする。  Therefore, a part of the refractory material 2 is replaced with a density increasing agent 3 containing no hydrogen so that the densities are equal.
そして、それぞれの密度'水素含有量を計算して、適度な置き換えを行なうこと により、 水素含有量がやや小さレ、耐火材 2部が高水素の中性子遮蔽材料 1で置換 されて、 水素含有量を増加させることができる。 Then, by calculating the density and hydrogen content of each, and performing appropriate replacement, the hydrogen content is slightly smaller, and 2 parts of the refractory material are replaced with high hydrogen neutron shielding material 1. Thus, the hydrogen content can be increased.
この結果、 二次 γ線の遮蔽性能を維持しながら中性子吸収量を上げることがで き、 これにより従来のように中性子遮蔽体本体の外側に γ線遮蔽用の構造物を配 置することなく、 中性子線の遮蔽性能を向上させることができる。  As a result, it is possible to increase the neutron absorption while maintaining the shielding performance of the secondary γ-rays, thereby eliminating the necessity of disposing a γ-ray shielding structure outside the neutron shield main body as in the conventional case. The neutron shielding performance can be improved.
また、 本実施の形態による中性子遮蔽体においては、 混合する密度増加剤 3の 密度を、 5. OgZmL以上、好ましくは 5. 0〜22. 5g/mL、 より好ましく は 6. 0〜1 5gZmLにすることにより、 上述した作用効果を、 より一層顕著に 奏することができる。  In the neutron shield according to the present embodiment, the density of the density increasing agent 3 to be mixed is set to 5.OgZmL or more, preferably 5.0 to 22.5 g / mL, more preferably 6.0 to 15 gZmL. By doing so, the above-described functions and effects can be more remarkably exhibited.
すなわち、 第 2図は、 密度増加剤 3の密度と水素含有量との関係を示す特性図 である。  That is, FIG. 2 is a characteristic diagram showing the relationship between the density of the density increasing agent 3 and the hydrogen content.
第 2図では、 水素含有量が 0. 096 9 g/mLであり、 耐火材 2 (水酸化マ グネシゥム） を含む密度 1. 64 g/mLのベース樹脂 1に、 密度が一定となる ように耐火材 2を密度増加剤 3で置換していった時の水素含有量を示している。 なお、耐'火材 2である水酸化マグネシウムの密度は、 2. 36 g/mLである。 第 2図からわかるように、 効果が認められるためには、 密度増加剤の密度を耐 火材 2 (2. 36 g/mL) の密度以上とすればよいわけではない。 すなわち、 ベース樹脂 1および耐火材 2の組み合わせによって異なるが、 耐火材 2 (2. 3 6 g/mL) の密度よりもやや高い密度が境界である。 第 2図に示すように、 密 '度増加剤 3の密度が、 5. 0 g/m L以上、好ましくは 6. 0 g/m L以上で効果が 認められる。 なお、密度増加剤 3の密度が 22. 5 g/mLを超えると添加量に応 じた効果は認められない。  In Fig. 2, the hydrogen content is 0.0969 g / mL and the refractory material 2 (magnesium hydroxide) is included in the base resin 1 with a density of 1.64 g / mL. It shows the hydrogen content when refractory material 2 was replaced with density increasing agent 3. The density of magnesium hydroxide, which is the refractory material 2, is 2.36 g / mL. As can be seen from Fig. 2, in order for the effect to be recognized, it is not necessary to set the density of the density increasing agent to be higher than that of refractory material 2 (2.36 g / mL). In other words, the density differs depending on the combination of the base resin 1 and the refractory material 2, but the boundary is a density slightly higher than the density of the refractory material 2 (2.36 g / mL). As shown in FIG. 2, the effect is observed when the density of the density increasing agent 3 is 5.0 g / mL or more, preferably 6.0 g / mL or more. If the density of Density Increasing Agent 3 exceeds 22.5 g / mL, the effect according to the amount added is not observed.
第 3図は、 密度増加剤 3の密度と中性子遮蔽体外側の中性子線 +二次 γ線量相 対比との関係を示す特性図である。  FIG. 3 is a characteristic diagram showing the relationship between the density of the density increasing agent 3 and the relative neutron beam + secondary γ dose outside the neutron shield.
第 3図では、'水素含有量が 0. 096 9 g /m Lであり、 耐火材 2 (水酸化マ グネシゥム） を含む密度 1. 64 gZmLのベース樹脂 1に、 .密度が一定となる ように耐火材 2を密度増加剤 3で置換していった時の遮蔽効果を示している。 . なお、 ベース樹脂 1の遮蔽外側線量を 1としている。 第 3図から、 効果が認められるのは、 密度増加剤 3の密度が 5. Og/m以上、 より好ましくは 6. OgZmL以上となっていることがわかる。 なお、 密度増加剤 3.の密度が、 22. 5 gZmLを超えると添加量に応じた効果は認められない。 さらに、 本実施の形態による中性子遮蔽体においては、 密度増加剤 3として、 融点が 350°C以上の金属粉 （Cr、 Mn、 Fe、 Ni、 Cu、 Sb、 Bi、 U、 W 等） を混合する力、 あるいは融点が 1000°C以上の金属の酸化物粉 （NiO、 C uO、 ZnO、 Zr〇2、 SnO、 S n 02、 W02、 Ce〇2、 U〇2、 P b 0、 P b O 、 wo3) を混合していることにより、 耐火性を向上させることができる。 In Fig. 3, the hydrogen content is 0.0969 g / mL, and the refractory material 2 (magnesium hydroxide) is contained in the base resin 1 with a density of 1.64 gZmL. Fig. 3 shows the shielding effect when the refractory material 2 was replaced with the density increasing agent 3. Note that the shielding outside dose of base resin 1 is 1. From FIG. 3, it can be seen that the effect is recognized because the density of the density increasing agent 3 is at least 5. Og / m, more preferably at least 6. OgZmL. If the density of the density increasing agent 3. exceeds 22.5 gZmL, the effect according to the added amount is not recognized. Furthermore, in the neutron shield according to the present embodiment, metal powder (Cr, Mn, Fe, Ni, Cu, Sb, Bi, U, W, etc.) having a melting point of 350 ° C or more is mixed as the density increasing agent 3. to force or melting point oxide powder 1000 ° C or more metals (NiO, C uO,, ZnO, Zr_〇 2, SnO, S n 0 2, W0 2, Ce_〇 2, U_〇 2, P b 0, P b O, by which a mixture of wo 3), it is possible to improve the fire resistance.
上述したように、 本実施の形態による中性子遮蔽体では、 材料の密度を下げず に一定の値に維持しながら水素含有量を増加させることができ、 これにより従来 のように中性子遮蔽体本体の外側に γ線遮蔽用の構造物を配置することなく、 中 性子線の遮蔽性能を向上させることが可能となる。  As described above, in the neutron shield according to the present embodiment, it is possible to increase the hydrogen content while maintaining a constant value without reducing the material density. It is possible to improve neutron shielding performance without arranging gamma-ray shielding structures on the outside.
(第 2の実施の形態）  (Second embodiment)
本実施の形態による中性子遮蔽体も、 前記第 1図に示すように、 高分子を主体 とした中性子遮蔽材料 1である水素含有量が低いエポキシ樹脂に、 耐火材 2と、 当該耐火材 2よりも密度が高い密度増加剤 3とを混合し、 硬ィ匕成形加工したもの としている。  As shown in FIG. 1, the neutron shield according to the present embodiment also includes, as shown in FIG. 1, an epoxy resin having a low hydrogen content, which is a neutron shielding material 1 mainly composed of a polymer, a refractory material 2, and a refractory material 2. Also, the mixture is mixed with a density increasing agent 3 having a high density and subjected to a shaping process.
ここで、 特に密度増加剤 3としては、 金属粉を混合したり、 あるいは金属の酸 化物粉を混合することにより、 水素含有量が低いエポキシ樹脂を硬化させた中性 子遮蔽体としている。  Here, in particular, as the density increasing agent 3, a neutron shield obtained by curing an epoxy resin having a low hydrogen content by mixing a metal powder or a metal oxide powder.
また、 混合する密度増加剤 3の密度は、 5. OgZmL以上、 好ましくは 5.0 ~22. 5g/mL、 より好ましくは 6.0〜15g/mLである。  The density of the density increasing agent 3 to be mixed is 5. OgZmL or more, preferably 5.0 to 22.5 g / mL, more preferably 6.0 to 15 g / mL.
さらに、 密度増加剤 3としては、 融点が 350°C以上の金属粉を混合するか、 あるいは融点が 1000 °C以上の金属の酸化物粉を混合することが好ましい。 これらに該当する粉体の材料として、 金属では、 例えば Cr、 Mn、 Fe、 Ni、 Cu、 Sb、 Bi、 U、 W等が挙げられる。  Further, as the density increasing agent 3, it is preferable to mix metal powder having a melting point of 350 ° C. or more, or to mix metal oxide powder having a melting point of 1000 ° C. or more. Examples of powder materials corresponding to these include metals such as Cr, Mn, Fe, Ni, Cu, Sb, Bi, U, and W.
また、 金属の酸化物では、 例えば NiO、 CuO、 Zn〇、 Zr〇2、 SnO、 S n〇2、 W02、 Ce〇2、 U〇2、 P b 0、 P b〇、 W〇3等が挙げられる。 In an oxide of a metal, for example NiO, CuO, Zn_〇, Zr_〇 2, SnO, S N_〇 2, W0 2, Ce_〇 2, U_〇 2, P b 0, P B_〇, W_〇 3, and the like.
なお、 高分子を主体とした中性子遮蔽材料 1としては、 エポキシ樹脂以外に、 例えばポリエチレン、 ポリプロピレン、 ポリブチレン等のポリオレフイン系樹-脂 等が、 代表的なものとして挙げられる。  In addition, as the neutron shielding material 1 mainly composed of a polymer, in addition to the epoxy resin, for example, a polyolefin resin such as polyethylene, polypropylene, polybutylene, or the like can be cited as a typical example.
次に、 以上のように構成した本実施の形態による中性子遮蔽体においては、 高 分子を主体とした中性子遮蔽材料 1に、 耐火材 2と、 当該耐火材 2よりも密度が 高い密度増加剤 3とを混合していることにより、 材料の密度を下げずに一定の値 に維持しながら （1 . 6 2〜1 . 7 2 g/m Lの範囲） 、 水素含有量を増加させる ことができる。  Next, in the neutron shielding body according to the present embodiment configured as described above, a neutron shielding material 1 mainly composed of a high molecule is added to a refractory material 2 and a density increasing agent 3 having a higher density than the refractory material 2. , It is possible to increase the hydrogen content while maintaining a constant value (in the range of 1.62 to 1.72 g / mL) without reducing the density of the material .
すなわち、 耐火材 2は、 .中性子遮蔽材料 1よりも密度がやや高く、 やや少ない 水素が含有する。  That is, the refractory material 2 has a slightly higher density than the neutron shielding material 1 and contains slightly less hydrogen.
そこで、 耐火材 2の一部を、 水素を含まない密度増加剤 3で置き換え、 密度が 同等となるようにする。  Therefore, a part of the refractory material 2 is replaced with a density increasing agent 3 containing no hydrogen so that the densities are equal.
そして、それぞれの密度'水素含有量を計算して、適度な置き換えを行なうこと により、 水素含有量がやや小さレ、耐火材 2部が高水素の中性子遮蔽材料 1で置換 されて、 水素含有量を増加させることができる。  Then, by calculating the density and hydrogen content of each, and performing an appropriate replacement, the hydrogen content is slightly smaller, and 2 parts of the refractory material is replaced with high-hydrogen neutron shielding material 1 and the hydrogen content is reduced. Can be increased.
この結果、 二次 γ線の遮蔽性能を維持しながら中性子吸収量を上げることがで き、 これにより従来のように中性子遮蔽体本体の外側に γ線遮蔽用の構造物を配 置することなく、 中性子線の遮蔽性能を向上させることができる。  As a result, it is possible to increase the neutron absorption while maintaining the shielding performance of the secondary γ-rays, thereby eliminating the necessity of disposing a γ-ray shielding structure outside the neutron shield main body as in the conventional case. The neutron shielding performance can be improved.
また、 本実施の形態による中性子遮蔽体においては、 混合する密度増加剤 3の 密度を、 5 . O gZm L以上、好ましくは 5. 0〜2 2 . 5 gZm L、 より好ましく は 6 . 0〜1 5 g/m Lにすることにより、 上述した作用効果を、 より一層顕著に 奏することができる。 Further, in the neutron shield according to the present embodiment, the density of the density increasing agent 3 to be mixed is set to 5.0 gZmL or more, preferably 5.0 to 22.5 gZmL, more preferably 6.0 to 5.0 gZmL. By adjusting the amount to 15 g / mL, the above-mentioned effects can be more remarkably exhibited.
すなわち、 第 2図は、 密度増加剤 3の密度と水素含有量との関係を示す特性図 である。  That is, FIG. 2 is a characteristic diagram showing the relationship between the density of the density increasing agent 3 and the hydrogen content.
第 2図では、 永素含有量が 0 . 0 9 6 9 g /m Lであり、 耐火材 2 (水酸化マ グネシゥム） を含む密度 1 . 6 4 g /m Lのベース樹脂 1に、 密度が一定となる ように耐火材 2を密度増加剤 3で置換していった時の水素含有量を示している。 なお、耐火材 2である水酸ィヒマグネシウムの密度は、 2. 36 g/mLである。. 第 2図からわかるように、 効果が認められるためには、 密度増加剤の密度を耐 火材 2の密度 （2. 36 g/mL) 以上とすればよいわけではない。 すなわち、 ベース樹脂 1およぴ耐火材 2の組み合わせによって異なるが、 耐火材 2の密度 （ 2. 36 g/mL) よりもやや高い密度が境界である。 第 2図に示すように、 密 度増加剤 3の密度が、 5.0 g/m L以上、 より好ましくは 6.0 g/m L以上で効 果が認められる。 なお、密度増加剤 3の密度が 22. 5gZmLを超えると添加量 に応じた効果は認、められない。 In Fig. 2, the base resin 1 with a nitrogen content of 0.0969 g / mL and a refractory material 2 (magnesium hydroxide) with a density of 1.64 g / mL was added to the base resin 1. Becomes constant Thus, the hydrogen content when the refractory material 2 is replaced with the density increasing agent 3 is shown. The density of magnesium hydroxide, which is refractory material 2, is 2.36 g / mL. As can be seen from Fig. 2, in order for the effect to be recognized, it is not sufficient that the density of the density increasing agent be higher than that of refractory material 2 (2.36 g / mL). That is, the boundary is a density slightly higher than the density of the refractory material 2 (2.36 g / mL), although it depends on the combination of the base resin 1 and the refractory material 2. As shown in FIG. 2, the effect is observed when the density of the density increasing agent 3 is 5.0 g / mL or more, more preferably 6.0 g / mL or more. When the density of the density increasing agent 3 exceeds 22.5 gZmL, the effect according to the added amount is not recognized.
第 3図は、 密度増加剤 3の密度と中性子遮蔽体外側の中性子線 +二次 γ線量相 対比との関係を示す特性図である。  FIG. 3 is a characteristic diagram showing the relationship between the density of the density increasing agent 3 and the relative neutron beam + secondary γ dose outside the neutron shield.
第 3図では、 水素含有量が 0. 0969 g m Lであり、 耐火材 2 (水酸化マ グネシゥム） を含む密度 1. 64 g/mLのベース樹脂 1に、 密度が一定となる ように耐火材 2を密度増加剤 3で置換していった時の遮蔽効果を示している。 なお、 ベース樹脂 1の遮蔽外側線量を 1としている。  In Fig. 3, the hydrogen content is 0.0969 gm L and the refractory material 2 (magnesium hydroxide) contains 1.64 g / mL base resin 1 so that the density is constant. This shows the shielding effect when 2 is replaced with the density increasing agent 3. The shielding outside dose of the base resin 1 is set to 1.
第 3図から、効果が認められるのは、密度増カロ剤 3の密度が 5.0 g/m L以上、 好ましくは 6. Og/mL以上となっていることがわかる。 なお、 密度増加剤 3の 密度が 22. 5 g/mLを超えると添カ卩量に応じた効果は認められない。  From FIG. 3, it can be seen that the effect is recognized when the density of the density-enhancing agent 3 is 5.0 g / mL or more, preferably 6. Og / mL or more. Note that if the density of the density increasing agent 3 exceeds 22.5 g / mL, no effect according to the amount of the added kashi can be observed.
さらに、 本実施の形態による中性子遮蔽体においては、 密度増加剤 3として、 融点が 350°C以上の金属粉 （Cr、 Mn、 Fe、 Ni、 Cu、 S b、 Bi、 U、 W 等） を混合する力、 あるいは融点が 1000°C以上の金属の酸化物粉（NiO、 C uO、 ZnO、 Zr〇2、 SnO、 Sn〇2、 W〇2、 Ce〇2、 U〇2、 P b 0、 P b O 、 wo3) を混合していることにより、 耐火性を向上させることができる。 Furthermore, in the neutron shield according to the present embodiment, metal powder having a melting point of 350 ° C. or more (Cr, Mn, Fe, Ni, Cu, Sb, Bi, U, W, etc.) is used as the density increasing agent 3. mixing force or melting point 1000 ° C or more metal oxides powder (NiO, C uO,, ZnO, Zr_〇 2, SnO, Sn_〇 2, W_〇 2, Ce_〇 2, U_〇 2, P b 0 , PbO and wo 3 ) can improve the fire resistance.
上述したように、 本実施の形態による中性子遮蔽体でも、 材料の密度を下げず に一定の値に維持しながら水素含有量を増加させることができ、 これにより従来 のように中性子遮蔽体本体の外側に γ線遮蔽用の構造物を配置することなく、 中 性子線の遮蔽性能を向上させることが可能となる。 つまり、 密度増加剤を用いることにより γ線の遮蔽性能を維持しながら中性子 遮蔽効果をより上げることができるので、 従来のように中性子遮蔽体本体の外側 に重厚な γ線遮蔽用の構造物を配置する必要性を小さくすることができる。 . ( ν ) ホウ素化合物 As described above, even with the neutron shield according to the present embodiment, it is possible to increase the hydrogen content while maintaining a constant value without lowering the material density. It is possible to improve neutron shielding performance without arranging gamma-ray shielding structures on the outside. In other words, by using a density increasing agent, it is possible to further enhance the neutron shielding effect while maintaining the gamma ray shielding performance, so that a heavy gamma ray shielding structure is provided outside the neutron shield body as in the past. The necessity of arrangement can be reduced. (ν) Boron compound
ホウ素化合物は、 微量に配合され、 中性子の減速および吸収材としての機能を 有する。 中性子遮蔽体に微量に配合されるホウ素化合物は、 中性子吸収能を有す るものであればよく、 例えば低速および熱中性子に対して大きな吸収断面積を有 する窒化ホウ素、 無水ホウ酸、 ホウ素鉄、 正ホウ酸、 炭化ホウ素、 あるいはメタ ホゥ酸などのホゥ素化合物が挙げられ、 炭化ホウ素が特に好ましい。 化学的安定 性 （温度で変化しない、 水分を吸収しない等） が高く、 また、 高分子を主体とし た中性子遮蔽材料に影響を与えないためである。 ホウ素化合物は、 1種類のホウ 素化合物を用いても、 2種以上のホゥ素化合物を混合して用いてもよい。  The boron compound is blended in a small amount and has a function as a neutron moderator and absorber. The boron compound to be incorporated in the neutron shield in a trace amount may be any compound having a neutron absorption capability, such as boron nitride, boric anhydride, and boron iron having a large absorption cross section for slow and thermal neutrons. And boron compounds such as orthoboric acid, boron carbide, and metaboric acid. Boron carbide is particularly preferred. This is because it has high chemical stability (does not change with temperature, does not absorb moisture, etc.) and does not affect neutron shielding materials mainly composed of polymers. As the boron compound, one kind of boron compound may be used, or two or more kinds of boron compounds may be mixed and used.
ホウ素化合物は粉末で用いられ、 粒径および添加量は適宜調節して添加するこ とができる。 し力 し、 エポキシ樹脂内での分散性、 中性子に対する遮蔽性を考慮 すれば平均粒径は 1〜 2 0 0 μ m程度が好ましく、 1 0〜1 0 0 m程度がより 好ましく、 2 0〜5 0 μ πι程度が特に好ましい。 添加量は、 用いられるホウ素化 合物の種類、 他の成分の種類や含有量等によって変動するため、 規定することは 困難である力 組成物全体中、好ましくは 0 . 5〜 1 0質量％、特に好ましくは 0 . 5〜 3質量％である。 0 . 5質量％未満では加えたホゥ素化合物の中性子遮蔽材 としての効果が低く、 また、 1 0質量％を超えた場合はホウ素化合物を均一に分 散させることが困難になる。  The boron compound is used in the form of a powder, and the particle size and the amount added can be adjusted appropriately and added. In consideration of dispersibility in the epoxy resin and shielding properties against neutrons, the average particle size is preferably about 1 to 200 μm, more preferably about 100 to 100 m, and more preferably about 20 to 100 μm. About 50 μπι is particularly preferred. Since the amount of addition varies depending on the type of the boron compound used, the type and content of other components, etc., it is difficult to specify the amount. Preferably, the amount is 0.5 to 10% by mass in the whole composition. And particularly preferably 0.5 to 3% by mass. When the amount is less than 0.5% by mass, the effect of the added boron compound as a neutron shielding material is low. When the amount exceeds 10% by mass, it becomes difficult to uniformly disperse the boron compound.
ここで、 中性子遮蔽能、 γ線遮蔽能、 および耐火性の点から好ましい中性子遮 蔽体用組成物は、 水素添加エポキシ樹脂： 3 8 w t。/。、 アミン系硬化剤： 8 w t %、 耐火材 (M g O H2) ： 3 5 w t %、 密度増加剤 (C e 02) ： 1 8 w t %、 B4C ： 1 w t %の組成からなる中性子遮蔽体用組成物である。 Here, a preferable composition for a neutron shielding body from the viewpoint of neutron shielding ability, γ-ray shielding ability, and fire resistance is hydrogenated epoxy resin: 38 wt. /. , Amine-based curing agent: 8 wt%, the refractory material (M g OH 2): 3 5 wt%, the density increasing agent (C e 0 2): 1 8 wt%, B 4 C: consisting of 1 wt% of the composition It is a composition for a neutron shield.
( v i ) カーボン粉末  (vi) carbon powder
カーボン粉末は、 中性子遮蔽能力をより向上させるために添加される。 詳しく 説明すると、硬ィ匕前樹月旨を溶融栓付き密閉容器内で耐火条件温度 (外部 8 0 0 °C、 3 0分） とすると、 樹脂内部にボイドが発生し、 中性子遮蔽能が低下するおそれ がある。 ここで、 カーボン粉末を添加するとボイドの発生が抑制され、 中性子遮 蔽能力がより向上する。 Carbon powder is added to further improve the neutron shielding ability. In detail To explain, if the temperature of the refractory condition (external temperature: 800 ° C, 30 minutes) in a sealed vessel with a melting stopper, the voids are generated inside the resin and the neutron shielding ability is reduced. There is a risk. Here, when carbon powder is added, the generation of voids is suppressed, and the neutron shielding ability is further improved.
添加するカーボン粉末は、 例えばカーボンブラック、 グラフアイト、 活性炭な どであり、 カーボンブラックが特に好ましい。 購入のし易さとコスト面で利点を 有するためである。ここで、カーボン粉末は、 1種類のカーボン粉末を用いても、 2種以上のカーボン粉末を混合して用いてもよい。 添加量は、 カーボン粉末の種 類により適宜調節して添加することができるが、力一ボンブラックの場合 0 . 0 2 〜 4質量％が適当であり、 0 . 0 5〜0 . 3質量％が特に好ましレ、。 0 . 0 2質量％ 以上で効果が認められ、 0 . 0 5質量％以上で特に効果が顕著である。 また、 0 . 3質量％以下では粘度の顕著な上昇は認められない。一方、 4質量％を超えると、 カーボン粉末添加に伴って粘度が急激に上昇し、 また、 添加分だけ水素含有量が 低下することから、 添加量に見合った効果が認められない。  The carbon powder to be added is, for example, carbon black, graphite, activated carbon and the like, and carbon black is particularly preferred. This is because it has advantages in ease of purchase and cost. Here, as the carbon powder, one type of carbon powder may be used, or two or more types of carbon powder may be mixed and used. The amount of addition can be adjusted appropriately according to the type of carbon powder, and in the case of carbon black, it is preferably from 0.02 to 4% by mass, and from 0.05 to 0.3% by mass. Les, especially preferred. The effect is recognized at 0.02% by mass or more, and the effect is particularly remarkable at 0.05% by mass or more. At less than 0.3% by mass, no remarkable increase in viscosity is observed. On the other hand, if the content exceeds 4% by mass, the viscosity sharply increases with the addition of the carbon powder, and the hydrogen content decreases by the amount added, so that no effect commensurate with the added amount is observed.
また、 カーボン粉末を過剰に添加すると、 中性子遮蔽体の他の成分比率が低く なるため、 水素含有量が下がり中性子遮蔽能力が低下する傾向がみられる。  In addition, if the carbon powder is added excessively, the ratio of other components in the neutron shield decreases, so that the hydrogen content tends to decrease and the neutron shielding ability tends to decrease.
粒径は特に限定はされないが、 粒径が大きレヽとカーボン粉末が製造中に沈降す る恐れがあるので沈降しない程度で小さな粒径が好ましい。 沈降しない粒径につ いては、 その他の条件 （例えば、 組成物の温度、 粘度、 硬化速度等） によって大 きく作用されるため、 単純に数値で規定できない。  Although the particle size is not particularly limited, it is preferable that the particle size is small enough to prevent sedimentation since the particle size is large and the carbon powder may settle during the production. The particle size that does not settle cannot be simply specified by a numerical value because it is largely affected by other conditions (eg, the temperature, viscosity, curing rate, etc. of the composition).
( V i i ) その他  (V i i) Other
本発明の中性子遮蔽体用組成物には、 充填剤として、 シリカ、 ァノレミナ、 炭酸 カルシウム三酸ィ匕アンチモン、 酸化チタン、 アスベスト、 クレー、 マイ力等の粉 末のほか、 ガラス繊維等を添加してもよく、 また、 必要に応じ炭素繊維等を添カロ してもよい。 きらに必要に応じて、 離型剤としての天然ワックス、 脂肪酸の金属 塩、 酸アミ ド類、 脂肪酸エステル類等、 難燃剤としての塩化パラフィン、 ブロム トルエン、 へキサブロムトルエン、 三酸化アンチモン等、 着色剤としてのカーボ ンブラック、 ベンガラ等の他、 シランカップリング剤、 チタンカップリング剤等 を添加することができる。 The neutron shielding composition of the present invention contains, as fillers, powders such as silica, anoremina, calcium carbonate, trimonium antimony, titanium oxide, asbestos, clay, and my powder, as well as glass fibers. And carbon fiber or the like may be added as needed. If necessary, natural waxes as release agents, metal salts of fatty acids, acid amides, fatty acid esters, etc., paraffin chloride, bromotoluene, hexabromotoluene, antimony trioxide, etc. as flame retardants Carbo as colorant Silane coupling agents, titanium coupling agents, etc., in addition to black and red iron oxides.
( I I ) キャスク  (I I) Cask
本発明の組成物は、 エポキシ樹脂とその他の成分とを混合することによって調 製される。 中性子遮蔽体は、 中性子遮蔽体用組成物を成形したものである。 中性 子遮蔽体の成形におけるエポキシ樹脂の架橋は、 室温でも可能だが加熱により行 なうのが好ましい。 具体的な条件としては、 エポキシ樹脂の種類、 組成等によつ て異なるが、 5 0〜 2 0 0 °Cの温度条件にぉレ、て 1時間〜 3時間加熱を行なうこ とが好ましい。さらには、このような加熱処理は 2段階で行なうことが好ましく、 6 0〜 9 0 で 1時間〜 2時間加熱した後、 1 2 0〜 1 5 0 で 2時間〜 3時間 加熱処理することが好ましい。  The composition of the present invention is prepared by mixing an epoxy resin with other components. The neutron shield is obtained by molding a composition for a neutron shield. Crosslinking of the epoxy resin during molding of the neutron shield can be performed at room temperature, but is preferably performed by heating. Specific conditions vary depending on the type, composition, and the like of the epoxy resin, but it is preferable to perform heating for 1 hour to 3 hours under a temperature condition of 50 to 200 ° C. Further, such a heat treatment is preferably performed in two stages.After heating at 60 to 90 for 1 to 2 hours, heat treatment at 120 to 150 for 2 to 3 hours is preferable. preferable.
中性子遮蔽体は、 中性子を遮蔽する目的で用いられ、 例えば使用済み燃料を貯 蔵'輸送するためのキャスクなどに用いられる。このような輸送用のキャスクは、 公知技術を利用して製造することができる。 なお、 キャスクは、 燃焼を終えた使 用済み燃料集合体を収容、 貯蔵する容器である。 核燃料サイクルの終期にあって 燃焼を終え使用できなくなった核燃料集合体を、 使用済み燃料 （リサイクル燃料 ) という。 使用済み燃料は、 核***生成物 （F P) など高放射能物質を含むので 熱的に冷却する必要があるから、 原子力発電所の冷却ピットで所定期間 （3〜6 ヶ月間） 冷却される。 その後、 遮蔽容器であるキャスクに収納され、 トラックや 船舶等で再処理施設に搬送、 貯蔵される。 以下、 図を用いて、 本発明のキャスク をさらに詳細に説明する。  Neutron shields are used to shield neutrons, for example, in casks for storing and transporting spent fuel. Such a cask for transportation can be manufactured using a known technique. The cask is a container that stores and stores the spent fuel assemblies that have been burned. At the end of the nuclear fuel cycle, nuclear fuel assemblies that have been burned and have become unusable are called spent fuel (recycled fuel). Spent fuel contains high radioactive materials such as fission products (FP) and needs to be thermally cooled. Therefore, it is cooled in a cooling pit of a nuclear power plant for a predetermined period (3 to 6 months). After that, they are stored in a cask, which is a shielding container, and transported and stored in a reprocessing facility by truck or ship. Hereinafter, the cask of the present invention will be described in more detail with reference to the drawings.
第 4図は、 キャスクを示す斜視図である。 第 5図は、 第 4図に示したキャスク の軸方向断面図である。 第 6図は、 第 4図に示したキャスクの径方向断面図であ る。 キャスク 1 0 0は、 胴本体 1 0 1のキヤビティ 1 0 2内面をバスケット 1 3 0の外周形状に合わせて機械加工したものである。 キヤビティ 1 0 2内面の機械 加工は、 専用の加工装置によってフライス等によって加工する。 胴本体 1 0 1お よび底板 1 0 4は、 y線遮蔽機能を有する炭素鋼製の鍛造品である。 なお、 炭素 鋼の代わりにステンレス鋼を用いることもできる。胴本体 1 0 1と底板 1 0 4は、 溶接によって結合する。 また、 耐圧容器としての密閉性能を確保するため、 一次 蓋 1 1 0と胴本体 1 0 1との間には金属ガスケットを設けておく。 FIG. 4 is a perspective view showing a cask. FIG. 5 is an axial sectional view of the cask shown in FIG. FIG. 6 is a radial sectional view of the cask shown in FIG. The cask 100 is obtained by machining the inner surface of the cavity 102 of the body 101 so as to match the outer peripheral shape of the basket 130. The inner surface of the cavity 102 is machined by milling or the like using a dedicated processing device. The trunk body 101 and the bottom plate 104 are forged products made of carbon steel having a y-ray shielding function. In addition, carbon Stainless steel can be used instead of steel. The trunk body 101 and the bottom plate 104 are joined by welding. In addition, a metal gasket is provided between the primary lid 110 and the body 101 in order to ensure the sealing performance of the pressure vessel.
胴本体 1 0 1と外筒 1 0 5との間には、 水素を多く含有する高分子材料であつ て中性子遮蔽機能を有するレジン 1 0 6、 すなわち上述した中性子遮蔽体用組成 物が充填される。 また、 胴本体 1 0 1と外筒 1 0 5との間には、 熱伝導を行う複 数の銅製内部フィン 1 0 7が溶接されており、 レジン 1 0 6は、 内部フィン 1 0 7によつて形成される空間に流動状態で図示しないパイプ等を介して注入され、 冷却固化される。 なお、 内部フィン 1 0 7は、 放熱を均一に行うため、 熱量の多 い部分に高い密度で設けるようにするのが好ましい。 また、 レジン 1 0 6と外筒 1 0 5との間には、 数 mmの熱膨張しろ 1 0 8が設けられる。 熱膨張しろ 1 0 8 は、 ホットメルト接着剤等にヒーターを埋め込んだ消失型を外筒 1 0 5内面に配 し、 レジン 1 0 6を注入固化した後、 ヒーターを加熱して溶融排出することによ つて形成する。  Between the trunk body 101 and the outer cylinder 105, a resin 106, which is a polymer material containing a large amount of hydrogen and has a neutron shielding function, is filled with the neutron shielding composition described above. You. A plurality of copper internal fins 107 for heat conduction are welded between the body 101 and the outer cylinder 105, and the resin 106 is connected to the internal fins 107. It is injected into a space formed by a pipe or the like (not shown) in a flowing state and cooled and solidified. The internal fins 107 are preferably provided with a high density in a portion having a large amount of heat in order to uniformly radiate heat. Further, a thermal expansion margin 108 of several mm is provided between the resin 106 and the outer cylinder 105. As for the thermal expansion margin 108, dispose the heat dissipation adhesive with a heater embedded in a hot-melt adhesive, etc. on the inner surface of the outer cylinder 105, inject and solidify the resin 106, and then heat and melt and discharge the heater. It is formed by
' 羞部 1 0 9は、 一次蓋 1 1 0と二次蓋 1 1 1によって構成される。 一次盞 1 1 ' 0は、 γ線を遮蔽するステンレス鋼または炭素鋼からなる円盤形状である。また、 二次蓋 1 1 1も、 ステンレス鋼製または炭素鋼製の円盤形状であるが、 その上面 には、 中性子遮蔽体としてレジン 1 1 2、 すなわち上述した中性子遮蔽体が封入 されている。 一次蓋 1 1 0および二次蓋 1 1 1は、 ステンレス鋼製または炭素鋼 製のボルト 1 1 3によって胴本体 1 0 1に取り付けられている。 さらに、 一次蓋 1 1 0および二次蓋 1 1 1と胴本体 1 0 1との間には、 それぞれ金属ガスケット が設けられ、 内部の密封性を保持している。 また、 蓋部 1 0 9の周囲には、 レジ ■ ン 1 1 4を封入した補助遮蔽体 1 1 5が設けられている。 '' The shank 1 109 is composed of a primary lid 110 and a secondary lid 111. The primary sandalwood 1 1 '0 is in the form of a disk made of stainless steel or carbon steel that blocks gamma rays. The secondary lid 111 is also a disk made of stainless steel or carbon steel, and the upper surface thereof is filled with a resin 112 as a neutron shield, that is, the neutron shield described above. The primary lid 110 and the secondary lid 111 are attached to the trunk body 101 by bolts 113 made of stainless steel or carbon steel. Further, metal gaskets are provided between the primary lid 110 and the secondary lid 111 and the trunk main body 101, respectively, to maintain the internal sealing performance. Further, an auxiliary shield 115 enclosing the resin 114 is provided around the lid 109.
キャスク本体 1 1 6の両^ ί則には、 キャスク 1 0ひを吊り下げるためのトラニォ ン 1 1 7が設けられている。 なお、 第 4図では、 補助遮蔽体 1 1 5を設けたもの を示したが、 キャスク 1 0 0の搬送時には、 補助遮蔽体 1 1 5を取り外して緩衝 体 1 1 8を取り付ける （第 5図参照） 。 緩衝体 1 1 8は、 ステンレス鋼材によつ て作成された外筒 1 2 0内にレッドゥッド材などの緩衝材 1 1 9を組み込んだ構 造である。 バスケット 1 3 0は、 使用済み燃料集合体を収容するセル 1 3 1を構 成する 6 9本の角パイプ 1 3 2からなる。 角パイプ 1 3 2には、 アルミニウムま たはアルミユウム合金粉末に中性子吸収性能をもつ Bまたは B化合物の粉末を添 加したアルミニウム複合材またはアルミニウム合金を用いる。 また、 中性子吸収 材としては、 ボロンの他に力ドミゥムを用いることができる。 In both rules of the cask body 1 16, a trunnion 117 for suspending the cask 10 is provided. Although FIG. 4 shows the case where the auxiliary shield 115 is provided, when the cask 100 is transported, the auxiliary shield 115 is removed and the buffer 118 is attached (FIG. 5). See). The cushion 1 18 is made of stainless steel It has a structure in which a cushioning material 119 such as a reddish material is incorporated in an outer cylinder 120 created by the above method. The basket 130 is composed of sixty-nine square pipes 13 2 constituting a cell 13 1 for storing a spent fuel assembly. For the square pipe 132, use is made of an aluminum composite material or an aluminum alloy obtained by adding a powder of B or B compound having neutron absorption performance to aluminum or aluminum alloy powder. In addition, as a neutron absorber, force domes can be used in addition to boron.
上述したキャスク 1 0 0は、 1 0 0 トン級の大型装置であり、 本発明の中性子 遮蔽体用組成物をレジン 1 0 6， 1 1 2 , 1 1 4として用いることによって、 格 段の軽量化と、 十分な中性子遮蔽能および耐熱性を保持することができる.ととも に、 内部フィン 1 0 7を有するような複雑な構成を有する箇所においても、 その 流動性と可使時間の増大によってレジン 1 0 6， 1 1 2 , 1 1 4の铸込み作業に かかる時間と労力とを格段に低減することができ 0。  The above-described cask 100 is a large-scale device of a 100-ton class, and by using the neutron shielding composition of the present invention as the resin 106, 112, 114, a remarkably light weight is obtained. Neutron shielding capacity and heat resistance can be maintained, and at the same time, even in a complex structure having internal fins 107, the fluidity and pot life can increase. The time and labor required for loading the resin 106, 112, 114 can be reduced significantly.
また、 本発明の組成物は、 第 7図に示す板状部材からなるバスケットを内部に 有する胴本体を有するキャスクにも好適に用いられる。  Further, the composition of the present invention is suitably used for a cask having a trunk body having a basket formed of a plate-like member shown in FIG. 7 therein.
胴本体 2 0 1と外筒 2 0 5と 2枚の伝熱フイン 2 0 7とで囲まれる空間 2 0 9 には、 中性子を吸収するため、 中性子遮蔽能を有する水素を多く含有する高分子 材料であるレジン、 すなわち上述した中性子遮蔽体用組成物が充填される。 この 中性子遮蔽体用組成物を含む中性子遮蔽体によって、 リサイクル燃料集合体から 放出される中性子を遮蔽し、 キャスク 2 0 0の外部へ漏洩する中性子を規制値以 下に抑える。  The space 209 surrounded by the trunk body 201, the outer cylinder 205, and the two heat transfer fins 207 contains a polymer containing a large amount of hydrogen, which has neutron shielding ability, in order to absorb neutrons The resin, which is the material, that is, the neutron shielding composition described above is filled. The neutron shield including the neutron shield composition shields neutrons emitted from the recycled fuel assembly, and suppresses neutrons leaking to the outside of the cask 200 to a regulated value or less.
本発明の組成物は、このようなキャスク中の遮蔽体に限定されるものではな 中性子の拡散を防止する装置や施設において、 様々な個所に用いることができ、 効果的に中性子を遮蔽することができる。  The composition of the present invention is not limited to such a shield in a cask.It can be used in various places in a device or facility for preventing neutron diffusion, and can effectively shield neutrons. Can be.
(実施例）  (Example)
以下、 本発明の実施例を示し、 本発明について更に詳細に説明するが、 本発明 は下記実施例に限定されるものではない。  Hereinafter, the present invention will be described in more detail with reference to Examples of the present invention, but the present invention is not limited to the following Examples.
中性子遮蔽能は、 以下重量減少率で表される耐熱性で評価した。 重量減少のほ とんどは水であり、 水には中性子を減速させる効果がある水素が多く含まれるか らである。すなわち、重量減少率が大きいという試験結果は、耐熱性が低いため、 水分が減少し、 その結果中性子遮蔽能が小さくなるということを意味している。 The neutron shielding ability was evaluated based on the heat resistance represented by the weight loss rate below. Weight loss Most of the water is water, which contains a lot of hydrogen, which has the effect of slowing down neutrons. In other words, the test result that the weight loss rate is large means that the water resistance is reduced due to the low heat resistance, and as a result, the neutron shielding ability is reduced.
y線の遮蔽能は、 中性子遮蔽体用組成物の密度 （gZcm3) で評価される。密 度力 S1.62〜： L. 72 gZc m3程度あれば、 γ線を十分に遮蔽することができる The y-ray shielding ability is evaluated by the density (gZcm 3 ) of the neutron shielding composition. Density force S1.62 or later: L. About 72 gZc m 3 γ-rays can be sufficiently shielded
(実験例 1 ) 密度増加剤と水酸化マグネシゥム粉末の使用 (Experimental example 1) Use of density increasing agent and magnesium hydroxide powder
表 1の配合にてエポキシ樹脂を硬ィ匕させ、 耐熱性を比較した。 耐熱性は、 密閉 容器中で 200°CX 2, 000 h保持し、 室温にて開封後、 一昼夜放置して揮発 成分を除去した時の重量減少率で表した。 水素含有量は、 一般に CHN分析計で 測定され、本実施例においてはガス熱伝導度検出型 CHN分析計を用いて求めた。 水酸化マグネシゥム粉末は、 粒径が 3. 3 μ mのものを用いた。  The epoxy resin was stiffened with the composition shown in Table 1 and the heat resistance was compared. The heat resistance was expressed as a weight loss rate when the container was kept at 200 ° C for 2,000 h in a closed container, opened at room temperature, and left overnight to remove volatile components. The hydrogen content was generally measured with a CHN analyzer, and in this example, the hydrogen content was determined using a gas thermal conductivity detection type CHN analyzer. Magnesium hydroxide powder with a particle size of 3.3 μm was used.
材料 Material
エポキシ主剤 大都産業製 ェピキュア 801A (商品名） Epoxy base agent EPICURE 801A (trade name) manufactured by Daito Sangyo
エポキシ硬化剤 大都産業製 KD631 Epoxy hardener Daito Sangyo KD631
耐火剤 比較例 1 ：水酸化アルミニゥム粉末 住友化学製 CW-325LV 実施例 1、 2 ：水酸化マグネシゥム粉末 宇部マテリアルズ製 炭化ホウ素 共立窯業製 KS-44 Fireproofing agent Comparative Example 1: Aluminum hydroxide powder CW-325LV manufactured by Sumitomo Chemical Examples 1, 2: Magnesium hydroxide powder Boron carbide manufactured by Ube Materials KS-44 manufactured by Kyoritsu Ceramics
密度増加剤 銅粉 福田金属箔粉製 FCC-115A Density increasing agent Copper powder Fukuda metal foil powder FCC-115A
表 1 table 1
Figure imgf000024_0001
比較例 1では、 2 0 0 °C耐熱評価にて 3 . 2質量％の重量減少がみられた。 従 つて、 中性子遮蔽能の低下が推測される。
Figure imgf000024_0001
In Comparative Example 1, a weight reduction of 3.2% by mass was observed in the heat resistance evaluation at 200 ° C. Therefore, it is assumed that the neutron shielding ability decreases.
実施例 1では、 耐火剤を水酸化アルミニゥム粉末から水酸化マグネシゥム粉末 に代えることで、 耐熱性が大きく向上している。 しかし、 水酸化マグネシウムは 水素含有量が低いため、 水素含有量をほぼ一定にすると、 耐火剤混入量を削減し なければならず、 密度が低下する。 その結果、 中性子が吸収された時に γ線が発 生するが、 γ線の遮蔽能は、密度にほぼ比例するため、 Ί線の遮蔽能は低下する。 実施例 2では、 密度低下を防止するため、 銅粉を水酸化マグネシゥ.ム粉末と合 わせて添加した。 これにより、 水酸ィ匕マグネシウム粉末を使用しても、 比較例 1 ど同じ密度を維持することができ、 その結果 τ/線遮蔽能を維持する。 また、 水酸 化アルミニウム粉末を使用せず、 水酸化マグネシウム粉末を用いることで、 耐火 材混合比を下げても耐熱性を維持することができた。 In Example 1, the heat resistance was greatly improved by changing the refractory agent from aluminum hydroxide powder to magnesium hydroxide powder. However, magnesium hydroxide has a low hydrogen content, so if the hydrogen content is almost constant, the amount of refractory agent mixed must be reduced and the density will decrease. As a result, gamma rays are generated when neutrons are absorbed, but the shielding ability of gamma rays is reduced because the shielding ability of gamma rays is almost proportional to the density. In Example 2, copper powder was added together with magnesium hydroxide powder in order to prevent a decrease in density. Thereby, even if the hydroxide magnesium powder is used, the same density as in Comparative Example 1 can be maintained, and as a result, τ / line shielding ability is maintained. Also, by using magnesium hydroxide powder instead of aluminum hydroxide powder, it was possible to maintain heat resistance even when the mixing ratio of refractory materials was reduced.
(実験例 2 ) 水素添加エポキシ樹脂と水酸ィ匕マグネシウム粉末の使用 表 2の配合にてエポキシレジンを硬化させ、 耐熱性を比較した。 密閉容器中で 2 0 0 °C X 2 , 0 0 0 h保持し、 室温にて開封後、 一昼夜放置して揮発成分を除 去した時の重量減少率で表した。 水酸ィ匕マグネシウム粉末は、 粒径が 5 0 ^ の ものを用いた。 (Experimental example 2) Use of hydrogenated epoxy resin and magnesium hydroxide powder Epoxy resin was cured with the composition shown in Table 2 and heat resistance was compared. In a closed container The temperature was kept at 200 ° C. for 20,000 hours, opened at room temperature, and left for 24 hours to remove volatile components. The magnesium hydroxide powder used had a particle size of 50 ^.
材料 Material
エポキシ主剤 比較例 2 大都産業製 ェピキュア 801A (商品名） Epoxy base agent Comparative example 2 Epicure 801A (trade name) manufactured by Daito Sangyo
比較例 3 大都産業製 ェピキュア 801Aのビスフエノール Aを水 素添カ卩した材料 （水素添加ビスフヱノール A型ェポキ シ樹脂）  Comparative Example 3 A material obtained by adding hydrogenated bisphenol A of Epicure 801A manufactured by Daito Sangyo (hydrogenated bisphenol A type epoxy resin)
エポキシ硬化剤 大都産業製 KD631 Epoxy hardener Daito Sangyo KD631
耐火剤 比較例 2 ：水酸化アルミニゥム粉末 住友化学製 CW- 325LV 比較例 3 ：水酸化マグネシゥム粉末 ソブェクレー製 炭化ホウ素 共立窯業製 Refractory agent Comparative example 2: Aluminum hydroxide powder CW-325LV manufactured by Sumitomo Chemical Comparative example 3: Magnesium hydroxide powder Made by Sobeclay Boron carbide Made by Kyoritsu Ceramics
表 2  Table 2
Figure imgf000025_0001
比較例 2では、 2 0 0 °C耐熱評価にて 3 . 2質量。/。の重量減少がみられた。 従 つて、 中性子遮蔽能の低下が推測される。 耐火剤として使用している水酸ィ匕アル ミニゥム粉末の耐熱性が問題になっていると考えられた。
Figure imgf000025_0001
In Comparative Example 2, it was 3.2 mass in heat resistance evaluation at 200 ° C. /. Weight loss was observed. Therefore, it is assumed that the neutron shielding ability decreases. It was considered that the heat resistance of the hydroxyl-salt aluminum powder used as a refractory agent was problematic.
比較例 3では、 水酸化アルミニゥム粉末を水酸化マグネシゥム粉末に代えるこ とで、 耐^熱性は大きく向上した。 しかし、 水酸化マグネシウム自体 （M g. (OH ) 2) の水素含有量は水酸ィ匕アルミニウム自体 （A l (O H) 3) の水素含有量よ り低いので、 中性子遮蔽体の水素含有量も低下し、 中性子遮蔽能も低下する。 そ こで、 エポキシ主剤を水素添加したもの （水素添カ卩ビスフエノール A型エポキシ 樹脂） を用い、 水素含有量を向上させた。 In Comparative Example 3, aluminum hydroxide powder was replaced with magnesium hydroxide powder. Thus, the heat resistance was greatly improved. However, since the hydrogen content of magnesium hydroxide itself (M g. (OH) 2 ) is lower than the hydrogen content of aluminum hydroxide itself (A 1 (OH) 3 ), the hydrogen content of the neutron shield is And the neutron shielding ability also decreases. Therefore, the hydrogen content was improved by using a hydrogenated epoxy main agent (hydrogenated kamen bisphenol A type epoxy resin).
(実験例 3 ) 水素添加エポキシ樹月旨と水酸ィヒマグネシウム粉末と密度増加剤の 使用  (Experimental example 3) Hydrogenated epoxy resin, magnesium hydroxide powder and use of density increasing agent
表 3の配合にてエポキシレジンを硬化させ、 耐熱性を比較した。 耐熱性は、 実 験例 1、 2と同様にして求めた。 水酸化マグネシゥム粉末は、 粒径が 3 · 3 /i m のものを用いた。  The epoxy resin was cured with the formulation in Table 3 and the heat resistance was compared. The heat resistance was determined in the same manner as in Experimental Examples 1 and 2. Magnesium hydroxide powder having a particle size of 3.3 / 3 / im was used.
材料 Material
エポキシ主剤 比較例 4 大都産業製 ェピキュア 801A (商品名) Epoxy base material Comparative Example 4 Epicure 801A (trade name) manufactured by Daito Sangyo
実施例 3 大都産業製 ェピキュア 801Aのビスフエノ一ノレ Aを水 素添加した材料 （水素添加ビスフエノール A型ェボキ シ樹脂）  Example 3 A material obtained by adding hydrogen to bisphenol A of Epicure 801A manufactured by Daito Sangyo (hydrogenated bisphenol A type epoxy resin)
エポキシ硬化剤 大都産業製 KD631 Epoxy hardener Daito Sangyo KD631
耐火剤 比較例 4 ：水酸化アルミニウム粉末 住友化学製 CW-325LV ' 実施例 3 ：水酸化マグネシゥム粉末 宇部マテリアルズ製 炭化ホウ素 共立窯業製 KS-44 Refractory Comparative Example 4: Aluminum hydroxide powder Sumitomo Chemical CW-325LV 'Example 3: Magnesium hydroxide powder Ube Materials Boron carbide Kyoritsu Ceramics KS-44
密度増加剤 鉄粉 神戸産業錄鉄粉製 # 200 Density increasing agent Iron powder Kobe Sangyo Co., Ltd.
表 ·3 Table3
Figure imgf000027_0001
比較例 4では、 200°C耐熱評価にて 3. 2質量％の重量減少がみられた。 従 つて、 中性子遮蔽能の低下が推測される。
Figure imgf000027_0001
In Comparative Example 4, a weight loss of 3.2% by mass was observed in the heat resistance evaluation at 200 ° C. Therefore, it is assumed that the neutron shielding ability decreases.
実施例 3では、 エポキシ主剤を水素添加物 （水素添加ビスフエノール A型ェポ キシ樹脂） に、 耐火剤を水酸化マグネシウム粉末に変更し、 さらに、 鉄粉を添加 することで、 密度、 水素含有量、 耐熱性が改善された。 すなわち、 中性子線およ ぴ γ線に対する遮蔽性おょぴ耐熱性が向上した。  In Example 3, the density and hydrogen content were changed by changing the epoxy main agent to a hydrogenated product (hydrogenated bisphenol A type epoxy resin), the refractory agent to magnesium hydroxide powder, and further adding iron powder. The quantity and heat resistance were improved. That is, the shielding property and heat resistance against neutron rays and γ rays were improved.
(実験例 4 ) 粒径が 1. 5〜 15 mの水酸化マグネシゥム粉末の使用 下記に示す市販のェポキシネオ料と水酸化マグネシゥム粉末と炭化ホゥ素を室温、 真空下で混合、 脱泡し、 50 X 50X 10 Ommの型に流し込んで、 室温で一昼 夜硬化後、 130°CX 24 hの条件で完全硬化させ、 第 1図に示すサンプル 1を 作製した。 材料混合後の粘度は、 遮蔽体製造時の作業性を考慮し、 一般に 100 P a ' s以下としているが、ここでは、 30 P a ' sを目安として試験を行った。 これを第 8図に示す耐火試験容器 5に入れ、 全体を SUSの鋼板で密封し、 上面 試験片の中心部分に直径 5 mmのスズの溶融栓をつけた後、 800°Cの雰囲気下 で 30分間静置した。 すなわち、 一般的な材料の耐火条件でなく、 金属キャスク の使用条件に合わせ、 準密閉状態での耐火となる。 耐火試験容器 5は、 室温'大 気雰囲気の条件下に取り出すと、 溶融栓からしばらく炎がみられるが、 間もなく 自己消火する。 室温まで戻した後、 中性子遮蔽体を取り出し、 内部の状態と重量 残存率を測定し、 耐火後もある程度の中性子遮蔽能力を有しているかどうかを判 断した。重量残存率は、実験例 1、 2の耐熱性と同様の方法で求め、混合粘度は、 B型粘度計を用いて求めた。 また、 連続するボイドは、 中性子遮蔽体の任意の断 面を 1 Ommのメッシュに分割し、 それを貫通する空間部の有無が 1つにでもみ られるかで判断する。 連続するポイドが生成すると、 中性子が透過する経路がで き、 中性子遮蔽能力が大きく低下する。 (Experimental example 4) Use of magnesium hydroxide powder having a particle size of 1.5 to 15 m The following commercially available epoxine material, magnesium hydroxide powder and boron carbide were mixed and degassed at room temperature under vacuum. It was poured into a mold of X50 × 10 Omm, cured at room temperature for 24 hours, and then completely cured at 130 ° C. for 24 hours to produce Sample 1 shown in FIG. The viscosity after mixing the materials is generally set to 100 Pa's or less in consideration of workability in manufacturing the shield, but here, the test was performed using 30 Pa's as a guide. This was placed in a fireproof test container 5 shown in Fig. 8, the whole was sealed with a SUS steel plate, and a 5-mm diameter tin stopper was attached to the center of the upper surface test piece. Let stand for 30 minutes. In other words, it is not the fireproof condition of general materials, Fire resistance in a semi-closed state according to the use conditions of. When the fireproof test container 5 is taken out under the condition of room temperature and atmospheric atmosphere, a flame is observed for a while from the melting stopper, but the self-extinguishing will be performed soon. After returning to room temperature, the neutron shield was taken out, the internal state and the residual weight ratio were measured, and it was determined whether or not the neutron shield had a certain level of neutron shielding ability even after fire resistance. The residual weight was determined by the same method as in the heat resistance of Experimental Examples 1 and 2, and the mixed viscosity was determined by using a B-type viscometer. For continuous voids, the arbitrary cross section of the neutron shield is divided into 1-Omm meshes, and it is determined whether there is at least one space penetrating therethrough. The formation of continuous poids provides a path for neutrons to penetrate, greatly reducing neutron shielding capacity.
材料 Material
ェポキシ主剤：大都産業製 DT-448 (ビスフエノール A誘導体含有混合樹脂） エポキシ硬化剤：大都産業製 1-5731 (ァミン硬化剤) Epoxy main ingredient: Daito Sangyo DT-448 (Bisphenol A derivative-containing mixed resin) Epoxy curing agent: Daito Sangyo 1-5731 (Amine curing agent)
水酸化マグネシゥム粉末：粒径 50 m、 15 m、 5 i m ソブェクレー製、粒径 3 .3μ χη 宇部マテリアルズ製、 *立径 1.7μπι、 Ι. Ομηι Magnesium hydroxide powder: particle size 50 m, 15 m, 5 im Sovreclay, particle size 3.3 μχη Ube Materials, * standing diameter 1.7 μπι, Ι. Ομηι
協和化学製、 粒径 1.4μιη 神島化学製  Kyowa Chemical, particle size 1.4μιη Kamishima Chemical
炭化ホウ素：共立窯業製 KS-44 Boron carbide: KS-44 manufactured by Kyoritsu Ceramics
表 4 Table 4
Figure imgf000029_0001
Figure imgf000029_0001
*1 約 5 0 %の確率で連続ボイドを生じる。  * 1 Continuous voids occur with a probability of about 50%.
*2 約 3 0 %の確率で連続ボイドを生じる。 表 4に示すように実施例 4〜実施例 7において、 重量残存率 5 0 %以上で、 か つ、 中性子遮蔽体の表層を除いて、 連続するポイドが生成されにくい傾向が認め られた。 ここで、 重量残存率とは、 1 0 0 (%) —重量減少率 （°/0) で表された 数値である。 * 2 Continuous voids occur with a probability of about 30%. As shown in Table 4, in Examples 4 to 7, it was found that the residual weight ratio was 50% or more, and that there was a tendency that continuous voids were hardly generated except for the surface layer of the neutron shield. Here, the weight residual ratio is a numerical value represented by 100 (%) — weight loss ratio (° / 0 ).
(実験例 5 ) カーボン粉末の添カロ  (Experimental example 5) Caro addition of carbon powder
実験例 4と同様の試験方法にて、 カーボン粉末添加の効果を確認した （試行数 1〜5回） 。 カーボン粉末はシグマアルドリツチジャパン社製カーボンブラック (型番 05-1530- 5) を使用した。 また、密度増加剤として使用した N i粉は、 山石 金属製のものを用いた。 その結果、 表 5に示すように、 カーボン粉末を混合した 実施例 9〜実施例 1 4で効果が認められ、 特に実施例 1 1〜実施例 1 4では連続 ボイドの生成が認められなかった。 The effect of adding carbon powder was confirmed by the same test method as in Experimental Example 4 (1 to 5 trials). Carbon powder is carbon black manufactured by Sigma Aldrich Japan (Model No. 05-1530-5) was used. The Ni powder used as the density increasing agent was made of Yamaishi metal. As a result, as shown in Table 5, the effects were observed in Examples 9 to 14 in which the carbon powder was mixed, and particularly, in Examples 11 to 14, no generation of continuous voids was observed.
表 5 Table 5
Figure imgf000031_0001
Figure imgf000031_0001
*1 連続ボイドの出現確率が 5 0 %以上 1 0 0 %未満。  * 1 Appearance probability of continuous void is 50% or more and less than 100%.
*2 連続ボイドの出現確率が 0 %以上 5 0 %未満。  * 2 Appearance probability of continuous void is 0% or more and less than 50%.
(実験例 6 ) 水酸化マグネシゥム粉末の粒径とカーボン粉末の添加  (Experimental example 6) Particle size of magnesium hydroxide powder and addition of carbon powder
実験例 4と同様の試験方法にて、 水酸ィヒマグネシウム粉末とカーボン粉末添加 の効果を確認、した。 カーボン粉末はシグマァ/レドリツチジャパン社製カーボンブ ラック （型番 05 - 1530-5) を使用した。 また、密度増加剤として使用した N i粉は 、 山石金属製のものを用いた。 その結果、 表 6に示すように粒径が 1 . 5〜1 5 μ mの水酸化マグネシゥム粉末とカーボン粉末の 2つを組み合わせることによる 相乗効果により、 ボイドが発生しにくいという傾向が認められた。 断面の観察を 行なったところ、 耐火後、 水酸ィ匕マグネシウム粉末とカーボン粉末の相乗効果に より、 最も緻密な構造を保っていたのは、 実施例 1 8の水酸ィ匕マグネシウム粉末 の粒径が 3 . 3 μ mの場合であった。 In the same test method as in Experimental Example 4, magnesium hydroxide powder and carbon powder were added. The effect of was confirmed. The carbon powder used was a carbon black (Model No. 05-1530-5) manufactured by Sigma / Redlitsch Japan. The Ni powder used as the density increasing agent was made of Yamaishi Metal. As a result, as shown in Table 6, there was a tendency for voids to be less likely to occur due to the synergistic effect of combining the two powders, magnesium hydroxide powder with a particle size of 1.5 to 15 μm and carbon powder. . Observation of the cross section revealed that after fire resistance, the synergistic effect of magnesium hydroxide powder and carbon powder maintained the most compact structure. In this case, the diameter was 3.3 μm.
表 6 Table 6
Figure imgf000033_0001
Figure imgf000033_0001
(実験例 7 )水素添加したビスフヱノール A主剤 3 8 . 6 W t %に、脂環族ァミ ンを主成分とした硬化剤を 1 2 . 9 W t %を添加したエポキシ樹脂原料に、さらに 耐火材として水酸化マグネシゥム粉末（粒径未調整） を 3 0 . 0 W t %、 中性子吸 収剤として B 4Cを 1 . 5 W t %添加し、それからさらに鉛粉末を 1 7 . 0 W t %添 加し、 室温、 真空下で混合し、 これを型に流し込み、 室温にて 1日硬化後、 1 4 0°Cにて 10時間硬化させ、 実施例 22の中性子遮蔽体を得た。 (Experimental Example 7) An epoxy resin raw material obtained by adding 18.6 Wt% of a curing agent mainly containing alicyclic amine to 38.6 Wt% of a hydrogenated bisphenol A main agent was further added. 0 3 hydroxide Maguneshiumu powder (particle径未adjustment) as a refractory material. 0 W t%, 1 to B 4 C as a neutron absorption adsorbents. 5 W was added t%, then further lead powder 1 7. 0 W Add t%, mix at room temperature under vacuum, pour this into a mold, and cure at room temperature for 1 day. The mixture was cured at 0 ° C. for 10 hours to obtain a neutron shield of Example 22.
この材料の組成を分析したところ、水素一0.103g/mL,炭素一 0.581 gZmL、窒素一 0.025g/mL、 ホウ素一 0.019gZmL、マグネシウム一 0.187g/mL、鉛—0.279 /mLであり、密度は 1.64 Og/mLであつ た。  The composition of this material was analyzed to be 0.103 g / mL for hydrogen, 0.581 g / mL for carbon, 0.025 g / mL for nitrogen, 0.019 g / mL for boron, 0.187 g / mL for magnesium, and 0.279 / mL for lead. It was 1.64 Og / mL.
また、実施例 22の鉛（P b)以外の密度増加剤として、 Bi203(実施例 23)、 Zr02 (実施例 24) 、 Cu (実施例 25) を用いて中性子遮蔽体を得た。 Resulting Further, as the density increasing agent other than lead in Example 22 (P b), Bi 2 0 3 ( Example 23), Zr0 2 (Example 24), Cu neutron shielding body (Example 25) Was.
表 7は、 実施例 22、 23、 24と、 従来の金属粉添加なしの比較例 8 (BW R金属キャスク用中性子遮蔽体） の中性子遮蔽性能とを比較した結果を示す表で ある。 尚、 比較例 8の BWR金属キャスク用中性子遮蔽体は、 従来品に相当する ものを製造して用いた。  Table 7 is a table showing the results of comparing the neutron shielding performance of Examples 22, 23, and 24 with Comparative Example 8 (a neutron shield for a BWR metal cask) without the conventional metal powder addition. The neutron shield for a BWR metal cask of Comparative Example 8 was manufactured and used as a conventional product.
また、 金属粉あるいは金属の酸化物粉を添加せず、 水酸化アルミニウムのみで 水素含有量と密度を調整した一例を比較例 9に示している。 Comparative Example 9 shows an example in which the hydrogen content and the density were adjusted using only aluminum hydroxide without adding metal powder or metal oxide powder.
表 7 Table 7
試験番号 実施例 22 実施例 23 実施例 24 実施例 25 比較例 8 比較例 9 密度（g/mL) 1.64 1.588 1.565 1.620 1.618 1.738 水素含有量 Test number Example 22 Example 23 Example 24 Example 25 Comparative example 8 Comparative example 9 Density (g / mL) 1.64 1.588 1.565 1.620 1.618 1.738 Hydrogen content
0.103 0.103 0.102 0.098 0.094 1.044 (g/mL)  0.103 0.103 0.102 0.098 0.094 1.044 (g / mL)
成素 ¾量 Element
0.581 0.584 0.575 0.583 0.452 0.403 (g/mL)  0.581 0.584 0.575 0.583 0.452 0.403 (g / mL)
0.025 0.025 0.025 0.025 0.019 0.0180.025 0.025 0.025 0.025 0.019 0.018
(g/mL) (g / mL)
ホウ素含有量 Boron content
0.019 0.019 0.018 0.017 0.016 0.019 (g/mL)  0.019 0.019 0.018 0.017 0.016 0.019 (g / mL)
アルミ二クム含有量 Aluminum content
0.000 0.000 0.000 0.000 0.339 0.391 (g/mL)  0.000 0.000 0.000 0.000 0.339 0.391 (g / mL)
水酸化マク'、ネシゥム Mac hydroxide ', Nesium
0.187 0.181 ■ 0.178 0.187 0.000 0.000 含有量 (g/mL)  0.187 0.181 ■ 0.178 0.187 0.000 0.000 Content (g / mL)
密度増加剤含 0.279 0.214 0.214 0.040 0.279 0.214 0.214 0.040
- 0.000 有量 (g/mL) (Pb) (Bi) (Bi) (Cu)  -0.000 Amount (g / mL) (Pb) (Bi) (Bi) (Cu)
酸素含有量 Oxygen content
0.394 0.393 + 0.424 0.376 0.698 0.785 (g/mLゝ推定値）  0.394 0.393 + 0.424 0.376 0.698 0.785 (g / mL ゝ estimated value)
混合初期粘度 Initial mixing viscosity
2， 000 2, 000 2， 000 10, 000 25, 000 〉100, 000 (mPa - s)  2,000 2,000 2,000 10, 000 25,000〉 100,000 (mPa-s)
ト-タル線量 (比較 Total dose (comparison
0.76 0.81 0.77 0.98 1.00 0.76 例 8を 1とする）  0.76 0.81 0.77 0.98 1.00 0.76 Example 8 is 1)
800。Cx30min耐  800. Cx30min resistance
火試験後の重 70 69 69 70 74 70 量残存率 (Wt%) 表 7の実施例 2 2に示すように、 高分子を主体とした中性子遮蔽材に、 金属粉 を添加することにより、 材料の密度 （ 1 . 6 2〜 1 . 7 2 g/m Lの範囲） を下げ ずに水素含有量を増加させることができる。 Weight after fire test 70 69 69 70 74 70 Residual weight (Wt%) As shown in Example 22 of Table 7, by adding metal powder to a neutron shielding material mainly composed of a polymer, the density of the material (range of 1.62 to 1.72 g / mL) ) The hydrogen content can be increased without lowering.
その結果、 二次 γ線の遮蔽性能を維持しながら、 中性子吸収量を上げることが でき、 これより中性子線の遮蔽性能を向上させることができる。  As a result, it is possible to increase the neutron absorption amount while maintaining the shielding performance of the secondary γ-rays, thereby improving the shielding performance of the neutrons.
なお、 水酸化アルミニウムのみで水素含有量と密度を調整した場合は、 表 7の 比較例 9に示すように、 固形分の増加により、 混合初期粘度が大幅に増加する。 この場合、 遮蔽材の施工性が悪くなり、 製造コストアップや、 大型成形体の製 造が困難になるなどの弊害が出る。  When the hydrogen content and the density were adjusted only with aluminum hydroxide, as shown in Comparative Example 9 in Table 7, the initial viscosity of the mixture was significantly increased due to the increase in the solid content. In this case, the workability of the shielding material is degraded, resulting in an increase in manufacturing costs and a difficulty in manufacturing a large molded body.
(実験例 8 )水素添加を行なつていない一般のビスフエノール A主剤 3 8 . 7 W t %に、脂環族ァミンを主成分とした硬化剤を 1 2 . 9 W t %を添加したエポキシ 樹脂原料に、 さらに耐火材として水酸化マグネシウム粉末（粒径未調整） を 2 8 . 0 W t °ん 中性子吸収剤として B 4Cを 1 . 5 W t %添加し、 それからさらに C u 粉末を 1 9 . 0 ^\¥セ％添加し、室温、真空下で混合し、 これを型に流し込み、室温 にて 1日硬化後、 1 4 0 °Cにて 1 0時間硬化させ、 実施例 2 5の中性子遮蔽体を 得た。 (Experimental example 8) Epoxy obtained by adding 12.9 Wt% of a curing agent mainly composed of alicyclic amine to 38.7 Wt% of a general bisphenol A main agent not subjected to hydrogenation. To the resin material, 28.0 Wt ° of magnesium hydroxide powder (unregulated particle size) was added as a refractory material, and 1.5 Wt% of B 4 C was added as a neutron absorber, and then further Cu powder was added. 19.0 ^ \\% was added, mixed at room temperature under vacuum, poured into a mold, cured at room temperature for one day, and then cured at 140 ° C for 10 hours. Five neutron shields were obtained.
表 7は、 この実施例 2 5と従来の金属粉添加なしの比較例 8 ( B WR金属キヤ スク用中性子遮蔽体) の中性子遮蔽性能を比較した結果を示す表である。  Table 7 is a table showing the results of comparing the neutron shielding performance of Example 25 with Comparative Example 8 (a neutron shield for a BWR metal mask) without the addition of the conventional metal powder.
表 7の実施例 2 5に示すように、 高分子を主体とした中性子遮蔽材に、 金属粉 を添加することにより、 水素添加せず、 水素含有量を上げていないエポキシ榭月旨 を用いても、 従来品 （BWR金属キャスク用中性子遮蔽体） と同等の中性子線の 遮蔽性能を確保することができる。 これにより、 中性子遮蔽体の製造工程を簡略 化することができる。  As shown in Example 25 in Table 7, by adding metal powder to a neutron shielding material mainly composed of a polymer, it is possible to use an epoxy that has no hydrogen content and has no increased hydrogen content. In addition, the same neutron shielding performance as the conventional product (neutron shield for BWR metal cask) can be secured. Thereby, the manufacturing process of the neutron shield can be simplified.
尚、 本発明は、 上記各実施例に限定されるものではなく、 実施段階ではその要 旨を逸脱しない範囲で、種々に変形して実施することが可能である。また、各実施 の形態は可能な限り適宜組み合わせて実施してもよく、 その場合には組み合わせ た作用効果を得ることができる。さらに、上記各実施の形態には種々の段階の発明 が含まれており、開示される複数の構成要件における適宜な組み合わせにより、種 々の発明を抽出することができる。例えば、実施の形態に示される全構成要件から 幾つかの構成要件が削除されても、発明が解決しようとする課題の欄で述べた課 題の少なくとも一つが解決でき、発明の効果の欄で述べられている効果の少なく とも一つが得られる場合には、この構成要件が削除された構成を発明として抽出 することができる。 It should be noted that the present invention is not limited to the above-described embodiments, and can be implemented in various forms without departing from the spirit of the invention in the implementation stage. Further, the embodiments may be combined as appropriate as much as possible, and in such a case, the combined operation and effect can be obtained. Further, each of the above embodiments includes various stages of the invention. And various inventions can be extracted by an appropriate combination of a plurality of disclosed constituent features. For example, even if some components are deleted from all the components shown in the embodiments, at least one of the problems described in the section of the problem to be solved by the invention can be solved, and If at least one of the stated effects can be obtained, a configuration from which this component is deleted can be extracted as an invention.
以上、 詳細に説明したように、 本発明の中性子遮蔽体用組成物は、 高分子を主 体とした中性子遮蔽材料と粒径が 1 . 5〜 1 5 μ mの水酸化マグネシゥム粉末と を含有するため、 中性子を遮蔽するのに好適であり、 耐火性にも優れている。 ま た、 粒径を調整した水酸化マグネシゥム粉末を用いているため、 作業性が向上し ている。 さらにカーボン粉末を添加することにより、 より中性子遮蔽能を向上さ せることができる。  As described above in detail, the neutron shielding composition of the present invention contains a neutron shielding material mainly composed of a polymer and magnesium hydroxide powder having a particle size of 1.5 to 15 μm. Therefore, it is suitable for shielding neutrons and has excellent fire resistance. In addition, workability is improved because magnesium hydroxide powder with a controlled particle size is used. Further, by adding carbon powder, the neutron shielding ability can be further improved.
また、 本発明の中性子遮蔽体用組成物は、 高分子を主体とした中性子遮蔽材料 と耐火材と密度増加剤とを含有するため、 中性子および γ線を遮蔽するのに好適 であり、 耐火性に優れている。 さらに耐火材として水酸ィ匕マグネシウム粉末を選 択し、 その粒径を調整することにより作業性を向上させることができる。 さらに カーボン粉末を添加することにより、 より中性子遮蔽能を向上させることができ る。 また、 材料の密度を下げずに一定の値に維持しながら水素含有量を増加させ ることができ、 これにより中性子遮蔽体本体の外側に γ線遮蔽用の構造物を配置 することなく中性子線の遮蔽性能を向上させることが可能となる。  Further, the composition for a neutron shielding body of the present invention contains a neutron shielding material mainly composed of a polymer, a refractory material and a density increasing agent, so that it is suitable for shielding neutrons and γ-rays. Is excellent. Further, by selecting hydroxide magnesium powder as a refractory material and adjusting the particle size, workability can be improved. The neutron shielding ability can be further improved by adding carbon powder. In addition, it is possible to increase the hydrogen content while maintaining a constant value without lowering the density of the material, thereby enabling neutron radiation without disposing a gamma-ray shielding structure outside the neutron shield main body. Can improve the shielding performance.
また、 本発明の中性子遮蔽体用組成物は、 前記高分子を主体とした中性子遮蔽 材料を 2 0〜 5 5質量％と、 前記硬化剤を 4〜 5 5質量％と、 前記耐火材を 5〜 6 0質量％と、 前記密度増加剤を 5〜 4 0質量。/。と、 ホウ素化合物を 0 . 5〜 1 0質量％とを含有することを特徴とするため、 中性子および γ線を遮蔽するのに 好適であり、 耐火性にも優れている。  Further, the composition for a neutron shielding body of the present invention comprises: 20 to 55% by mass of the neutron shielding material mainly composed of the polymer; 4 to 55% by mass of the curing agent; 660% by mass, and the density increasing agent is 5 剤 40% by mass. /. And 0.5 to 10% by mass of a boron compound, so that it is suitable for shielding neutrons and γ-rays and has excellent fire resistance.
また、 本発明のキャスクは、 上記中性子遮蔽体用組成物を含む中性子遮蔽体を 有するので、 効果的に中性子および γ線を遮蔽することができる。 また、 本発明の中性子遮蔽体の製造方法は、 エポキシ樹脂以外の添加物の一部 を密度増加剤で置換することによって、 水素含有量を増加させることができる。 高分子を主体と'した中性子遮蔽材料以外の構成成分の一部置換を行なうことによ り、 中性子遮蔽体用組成物の比重を維持 (1. 6 2-1. 72 g/cm3) しながら 、 エポキシ樹脂の量を多くすることができるため水素含有量の高い中性子遮蔽体 を製造することができ、 効果的に中性子を遮蔽することができる。 すなわち、 中 性子遮蔽能と 線遮蔽能を両立させた中性子遮蔽体を製造することができる。 産業上の利用可能性 In addition, since the cask of the present invention has a neutron shield including the above-described composition for a neutron shield, it is possible to effectively shield neutrons and γ-rays. In the method for producing a neutron shield of the present invention, the hydrogen content can be increased by substituting a part of the additive other than the epoxy resin with a density increasing agent. The specific gravity of the neutron shielding composition is maintained (1.6 2-1.72 g / cm 3 ) by partially substituting components other than the neutron shielding material mainly composed of polymer. However, since the amount of epoxy resin can be increased, a neutron shield having a high hydrogen content can be manufactured, and neutrons can be effectively shielded. That is, a neutron shield having both a neutron shielding ability and a line shielding ability can be manufactured. Industrial applicability
以上のように、 本発明にかかる中性子遮蔽体用組成物は、 使用済燃料の貯蔵お よぴ運搬用のキャスクに適した中性子遮蔽体製造用の組成物に適している。  As described above, the composition for a neutron shield according to the present invention is suitable for a composition for producing a neutron shield suitable for a cask for storing and transporting spent fuel.

Claims

請 求 の 範 囲 The scope of the claims
1. 使用済み燃料集合体を収容するセル（1 31) を構成する角パイプ （132 ) 又は板状部材からなるバスケット （130) を内部に有する胴本体 （101) と、 1. A trunk body (101) having therein a square pipe (132) or a basket (130) made of a plate-like member constituting a cell (1 31) for storing a spent fuel assembly;
前記胴本体 （101) とその外周に設けられた外筒（105) との間に、 高分子 を主体とした中性子遮蔽材料と、 耐火材と、 密度増加剤とを含有する中性子遮蔽 体用組成物 （106) を充填してなる中性子遮蔽体と、  A composition for a neutron shielding body comprising a neutron shielding material mainly composed of a polymer, a refractory material, and a density increasing agent between the trunk body (101) and an outer cylinder (105) provided on the outer periphery thereof. A neutron shield filled with an object (106);
を有することを特徴とするキャスク (100) 。  A cask (100) characterized by having:
2. さらに蓋部 (109) が設けられており、 該蓋部は、 その上面および/ま たは周囲に、 高分子を主体とした中性子遮蔽材料と、 耐火材と、 密度増加剤とを 含有する中性子遮蔽体用組成物 (1 12、 1 14) が封入されていることを特徴 とする請求の範囲第 1項に記載のキャスク （100) 。 2. A lid (109) is further provided, and the lid contains a neutron shielding material mainly composed of a polymer, a refractory material, and a density increasing agent on its upper surface and / or periphery. The cask (100) according to claim 1, wherein a neutron shielding composition (112, 114) is sealed.
3. 使用済み燃料集合体を収容するセル （131) を構成する角パイプ （1 3 2) 又は板状部材からなるバスケット (130) を内部に有する胴本体 (101 と、 - 前記胴本体 (101) とその外周に設けられた外筒 (105) との間に、 高分 子を主体とした中性子遮蔽材料と、 耐火材として粒径が 1. 5〜 15 μ mの水酸 化マグネシウム粉末と、 密度増加剤とを含有する中性子遮蔽体用組成物 （106 ) を充填してなる中性子遮蔽体と、 3. A trunk body (101) having therein a square pipe (1 32) or a basket (130) made of a plate-like member constituting a cell (131) for storing a spent fuel assembly, and-the trunk body (101 ) And an outer cylinder (105) provided on the outer periphery of the neutron shielding material mainly composed of polymers, and magnesium hydroxide powder with a particle size of 1.5 to 15 μm as a refractory material. A neutron shield comprising a neutron shield composition (106) containing a density increasing agent;
を有することを特徴とするキャスク （100) 。  A cask (100) characterized by having:
4. さらに蓋部 （109) が設けられており、該蓋部は、 その上面および Zまた は周囲に、 高分子を主体とした中性子遮蔽材料と、 耐火材として粒径が 1. 5〜 1 5 mの水酸化マグネシウム粉末と、 密度増加剤とを含有する中性子遮蔽体用 組成物 （1 12、 1 14) が封入されていることを特徴とする請求の範囲第 3項 に記載のキャスク （100) 。 4. Further, a lid (109) is provided. The lid has a neutron shielding material mainly composed of a polymer on its upper surface and Z or its periphery, and a particle diameter of 1.5 to 1 as a refractory material. For neutron shield containing 5 m of magnesium hydroxide powder and density increasing agent Cask (100) according to claim 3, characterized in that the composition (112, 114) is encapsulated.
5. 使用済み燃料集合体を収容するセル （131) を構成する角パイプ （13 2) 又は板状部材からなるバスケット （1 30) を内部に有する胴本体 （101 と、 5. A trunk body (101 having a square pipe (13 2) or a basket (1 30) made of a plate-like member constituting a cell (131) for storing a spent fuel assembly,
前記胴本体 （101) とその外周に設けられた外筒 （105) との間に、 高分 子を主体とした中性子遮蔽材料と、 耐火材として粒径が 1. 5〜 15 μ mの水酸 化マグネシウム粉末とを含有する中性子遮蔽体用組成物 (106) を充填してな る中性子遮蔽体と、  A neutron shielding material mainly composed of a polymer and water having a particle size of 1.5 to 15 μm as a refractory material are provided between the trunk body (101) and an outer cylinder (105) provided on the outer periphery thereof. A neutron shield filled with a neutron shield composition (106) containing magnesium oxide powder;
を有することを特徴とするキャスク （100) 。  A cask (100) characterized by having:
6. さらに蓋部 (109) が設けられており、 該蓋部は、 その上面および/また は周囲に、 高分子を主体とした中性子遮蔽材料と、 耐火材として粒径が 1. 5〜 15 μ mの水酸化マグネシゥム粉末とを含有する中性子遮蔽体用組成物 (1 12、 1 14) が封入されていることを特徴とする請求の範囲第 5項に記載のキャスク (100) 。 6. A lid (109) is further provided. The lid is provided on its upper surface and / or periphery with a neutron shielding material mainly composed of a polymer and a particle diameter of 1.5 to 15 as a refractory material. 6. The cask (100) according to claim 5, wherein a composition for a neutron shield (112, 114) containing μm of magnesium hydroxide powder is enclosed.
7. キャスクに適した中性子遮蔽体製造用の組成物であって、 7. A composition for producing a neutron shield suitable for a cask,
高分子を主体とした中性子遮蔽材料と、 粒径が 1. 5〜 15 μ mの水酸化マグ ネシゥム粉末とを含有することを特徴とする中性子遮蔽体用組成物。  A neutron shielding composition comprising: a polymer-based neutron shielding material; and magnesium hydroxide powder having a particle size of 1.5 to 15 μm.
8. キャスクに適した中性子遮蔽体製造用の組成物であって、 8. A composition for producing a neutron shield suitable for a cask,
高分子を主体とした中性子遮蔽材料と、 耐火材と、 密度増加剤とを含有するこ とを特徴とする中性子遮蔽体用組成物。  A neutron shielding composition comprising a neutron shielding material mainly composed of a polymer, a refractory material, and a density increasing agent.
9. 前記高分子を主体とした中性子遮蔽材料が、 エポキシ樹脂であることを特 徴とする請求の範囲第 7項または第 8項に記載の中性子遮蔽体用組成物, 9. The neutron shielding material mainly composed of polymer is epoxy resin. The composition for a neutron shield according to claim 7 or claim 8,
1 0 . 前記高分子を主体とした中性子遮蔽材料が、 水素添加エポキシ樹脂であ ることを特徴とする請求の範囲第 7項または第 8項に記載の中' I"生子遮蔽体用組成 物 α 10. The composition according to claim 7, wherein the polymer-based neutron shielding material is a hydrogenated epoxy resin. α
1 1 . 前記高分子を主体とした中性子遮蔽材料が、 水素添加ビスフエノール A 型エポキシ樹脂であることを特徴とする請求の範囲第 7項または第 8項に記載の 中性子遮蔽体用組成物。 11. The neutron shielding composition according to claim 7, wherein the polymer-based neutron shielding material is a hydrogenated bisphenol A-type epoxy resin.
1 2 . 前記耐火材が、 水酸化マグネシゥム粉末であることを特徴とする請求の 範囲第 8項に記載の中性子遮蔽体用組成物。 12. The composition for a neutron shield according to claim 8, wherein the refractory material is magnesium hydroxide powder.
1 3 . 前記水酸化マグネシゥム粉末の粒径が、 1 . 5〜1 5 i mであることを 特徴とする請求の範囲第 1 2項に記載の中性子遮蔽体用組成物。 13. The neutron shielding composition according to claim 12, wherein the magnesium hydroxide powder has a particle size of 1.5 to 15 im.
1 4 . 前記密度増加剤が、 5 . 0 g /m L以上の密度であることを特徴とする 請求の範囲第 8項に記載の中性子遮蔽体用組成物。 14. The composition for a neutron shield according to claim 8, wherein the density increasing agent has a density of 5.0 g / mL or more.
1 5 . 前記密度増加剤が、 金属粉であることを特徴とする請求の範囲第 8項に 記載の中性子遮蔽体用組成物。 15. The composition for a neutron shield according to claim 8, wherein the density increasing agent is metal powder.
1 6 · 前記密度増加剤が、 金属の酸化物粉であることを特徴とする請求の範囲 第 8項に記載の中性子遮蔽体用糸且成物。 16. The yarn composition for a neutron shield according to claim 8, wherein the density increasing agent is a metal oxide powder.
1 7 . 前記密度増加剤が、 3 5 0 °C以上の融点を有する金属粉であることを特 徴とする請求の範囲第 1 5項に記載の中性子遮蔽体用組成物。 17. The neutron shielding composition according to claim 15, wherein the density increasing agent is a metal powder having a melting point of 350 ° C. or more.
18. 前記 350°C以上の融点を有する金属粉が、 Cr、 Mn、 F e、 N i、 Cu、 Sb、 B i、 U、 Wのうちいずれか 1つであることを特徴とする請求の範 囲第 17項に記載の中性子遮蔽体用組成物。 18. The metal powder having a melting point of 350 ° C. or more is any one of Cr, Mn, Fe, Ni, Cu, Sb, Bi, U, and W. Item 19. The composition for a neutron shield according to Item 17,
19. 前記密度増加剤が、 1000°C以上の融点を有する金属の酸化物粉であ ることを特徴とする請求の範囲第 16項に記載の中性子遮蔽体用糸且成物。 19. The yarn composition for a neutron shield according to claim 16, wherein the density increasing agent is a metal oxide powder having a melting point of 1000 ° C or more.
20. 前記 1000°C以上の融点を有する金属の酸化物粉が、 N i 0、 C u 0、 Z nO、 Z r 02、 S nO、 S n 02、 W〇2、 C e〇2、 U〇2、 PbO、 W03のう ちいずれか 1つであることを特徴とする請求の範囲第 19項に記載の中性子遮蔽 体用組成物。 20. The 1000 ° oxide powder of a metal having a C above melting point, N i 0, C u 0 , Z nO, Z r 0 2, S nO, S n 0 2, W_〇 2, C E_〇 2 , U_〇 2, PbO, W0 3 sac Chiizure or neutron shield-body composition according to claim 19, wherein claims, characterized in that is one.
21. さらに、 カーボン粉末を含有することを特徴とする請求の範囲第 7項ま たは第 8項に記載の中性子遮蔽体用組成物。 21. The composition for a neutron shield according to claim 7 or 8, further comprising a carbon powder.
22. 前記カーボン粉末が、 カーボンブラックであることを特徴とする請求の 範囲第 21項に記載の中性子遮蔽体用組成物。 22. The composition for a neutron shielding body according to claim 21, wherein the carbon powder is carbon black.
23. 前記カーボンブラックを 0.02〜4質量％含有することを特徴とする請 求の範囲第 22項に記載の中性子遮蔽体用組成物。 23. The composition for a neutron shield according to claim 22, wherein the composition contains 0.02 to 4% by mass of the carbon black.
24. キャスクに適した中性子遮蔽体製造用の組成物であって、 24. A composition for producing a neutron shield suitable for a cask,
高分子を主体とした中性子遮蔽材料を 20〜 55質量％と、 硬化剤を 4〜 55 質量％と、 耐火材を 5〜 60質量％と、 密度増加剤を 5〜 40質量。 /0と、 ホウ素 化合物を 0. 5〜 10質量％とを含有することを特徴とする中性子遮蔽体用組成 物。 20-55% by mass of polymer-based neutron shielding material, 4-55% by mass of hardener, 5-60% by mass of refractory, and 5-40% by mass of density increasing agent. / 0, the neutron shielding-body composition characterized by containing a boron compound from 0.5 to 10 wt%.
25. 構成成分として高分子を主体とした中性子遮蔽材料を含有し、 T線の遮 蔽' I·生能を維持しつつ、 中性子遮蔽効果を上げることができる中性子遮蔽体の製造 法であって、 25. A method for producing a neutron shielding body that contains a neutron shielding material mainly composed of a polymer as a constituent and can enhance a neutron shielding effect while maintaining T-ray shielding ' ,
前記高分子を主体とした中性子遮蔽材料以外の構成成分を密度増加剤で置換す ることにより、 中性子遮蔽体用組成物の比重を 1. 62〜： L. 72 gZc m3に維 持することを特徴とする中性子遮蔽体製造法。 The specific gravity of the neutron shielding composition is maintained at 1.62 to: L. 72 gZcm 3 by replacing the components other than the polymer-based neutron shielding material with a density increasing agent. A method for producing a neutron shield, comprising:
26. 前記高分子を主体とした中性子遮蔽材料以外の構成成分が、 耐火材であ ることを特徴とする請求の範囲第 25項に記載の中性子遮蔽体製造法。 26. The method for producing a neutron shield according to claim 25, wherein the constituent component other than the neutron shielding material mainly composed of a polymer is a refractory material.
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